Tools for Developer

580 hand-picked tools for Developer. Free, private, browser-based.

555 Timer Calculator

Astable f = 1.44/((R1+2R2)C) + monostable t = 1.1RC — pick R1, R2, C in Ω/kΩ and µF/nF, read frequency, duty cycle and pulse width — browser-only
Add Line Numbers

Number every line of pasted text — set start, step and separator, zero-pad to align, skip blanks, or strip numbers back off — browser-only
AES Text Encryptor

Encrypt & decrypt text with a password — AES-256-GCM + PBKDF2 via WebCrypto — 100% in your browser, nothing uploaded
Affine Cipher Encoder & Decoder

Encrypt and decrypt the ax+b affine cipher with live modular-inverse check, browser-only
Age Difference Calculator

The exact gap between two birthdays — years/months/days, percentage, and the date one person is twice the other's age — browser-only
AI Eval Planner

Generate eval cases, pass criteria, and edge cases from an AI feature, risks, and user path.
AI Model Comparison

AI model comparison — 20+ models (GPT / Claude / Gemini / Llama / Qwen) across price, context, speed, capabilities (2026).
AI Token Counter

AI token counter — estimate token count for GPT / Claude / Gemini, with per-model cost calculator (2026 pricing).
Angle Converter

Degrees, radians, gradians, turns, arcminutes, arcseconds and NATO mils, all from one input, copyable, browser-only
Antenna Length Calculator

Frequency in MHz to dipole, quarter-wave and full-wave length, with velocity factor, in metres or feet, browser-only
Apache Cheatsheet

Apache HTTP Server cheatsheet for httpd.conf, VirtualHost, .htaccess, mod_rewrite, SSL, proxying, auth, headers, and logs.
API Key Generator

Generate cryptographically random API keys and secret tokens with a custom prefix, length, and charset, with a live entropy readout, entirely in your browser.
API Rate Limit Cheatsheet

Search rate-limit headers, retry rules, provider quirks, and paste 429 headers to decode the next safe retry
App Store Keywords Checklist

Validate your App Store title, subtitle and 100-char keyword field before launch — live character counts, keyword overlap detection, asset checklist
Armstrong Number Checker

Test if a number equals the sum of its digits each raised to the digit count (153 = 1^3 + 5^3 + 3^3), with full breakdown and a range list. Browser-only.
ASCII Art Generator

Generate ASCII art from text — figlet-style banners, multiple fonts.
ASCII Table Generator

Paste CSV or TSV, get a monospace table that lines up: +--+ ASCII, Unicode box, Markdown, with real CJK width
ASCII Table Reference

Complete 0–127 ASCII table: decimal, hex, octal, binary, character, name, HTML entity and escape — control codes explained, click to copy, fully searchable.
Aspect Ratio Calculator

Calculate aspect ratio — fix any 1 of [width, height, ratio], get the other two.
Atbash Cipher

Mirror the alphabet, A↔Z B↔Y, no key, self-reciprocal so the same button encodes and decodes, browser-only
Avatar Generator

Generate avatars from initials, identicons, or random shapes. Download PNG/SVG.
awk + sed Cheatsheet

awk + sed cheat sheet — 80+ one-liners for text processing, with real examples and common pitfalls.
AWS CLI Cheatsheet

AWS CLI cheat sheet — 80+ commands for EC2 / S3 / IAM / Lambda / RDS / EKS / CloudFormation with real examples.
AWS IAM Cheatsheet

Search AWS IAM policy fields, ARNs, conditions, managed policies, trust rules, and inspect policy JSON locally.
AWS S3 Cheatsheet

AWS S3 cheat sheet — 58+ commands covering buckets, sync, presign, versioning, lifecycle, encryption, CORS, and multipart.
Backup Codes Generator

Generate 2FA backup and recovery codes the GitHub way, formatted, unique, and made in your browser
Bacon Cipher Encoder & Decoder

Turn text into five-letter A/B groups, or read a Baconian message back — 24 and 26 letter alphabets, custom symbols, browser only
Barcode Generator

Code 128 / EAN-13 / UPC-A / Code 39 — generate scannable 1D barcodes, export SVG or PNG, fully offline.
Number Base Converter

Number base converter — binary, octal, decimal, hex, and any base 2-36. Bitwise too.
Base32 / Base58 Encoder & Decoder

Base32 + Base58 encoder/decoder — RFC 4648 base32 (Crockford variant too), Bitcoin base58, Solana base58, hex/text/file input.
Base62 Encoder & Decoder

Turn big integers and UTF-8 text into compact 0-9A-Za-z strings, the way short-URL services pack an ID into 6 characters, all in your browser
Base64 Block Deduplicator

Find duplicates and keep one clean copy of base64 blocks from pasted text or uploaded local files.
Base64 Block Extractor

Extract, dedupe, and export base64 blocks from pasted text or uploaded local files.
Base64 Block List Converter

Convert base64 blocks from pasted text or uploaded local files.
Base64 Block List Validator

Validate and explain issues in base64 blocks from pasted text or uploaded local files.
Base64 Block Normalizer

Normalize, sort, and prepare base64 blocks from pasted text or uploaded local files.
Base64 Encoder & Decoder

Encode or decode Base64 — text, files, and Data URLs. Runs entirely in your browser.
Base64 Image Converter

Image ⇄ Base64 — drag-drop PNG/JPG/WebP/SVG, get data URI for CSS / HTML / Markdown.
Base64 Image Data URI Converter

Convert images to data URIs (base64 or URL-encoded), inspect any data URI, preview and download. 100% in-browser.
Base64 to File Converter

Paste raw Base64 or a data URL, decode it locally, inspect bytes, and download the reconstructed file.
Base64 to Hex Converter

Base64 ⇄ hexadecimal at the byte level, no text encoding in between — standard or URL-safe, your separator and case, runs in your browser
Base64URL Encoder Decoder for JWT-Safe Strings

Encode and decode URL-safe Base64 strings for JWT headers, payloads, tokens, and URL parameters without padding surprises.
Base85 / Ascii85 Encoder & Decoder

Encode text to Ascii85 or Z85 and decode it back, UTF-8 safe, with z-compression and <~ ~> handling, all in your browser
Bash Cheatsheet

Bash cheat sheet — 100+ commands & idioms for variables, conditionals, loops, functions, pipes, traps, with real one-liners.
Basic Auth Header Generator

Username plus password into Authorization Basic base64, with curl -u and -H examples, plus reverse decoding, all in your browser
Batch File Rename Planner

Upload a batch, generate safe new filenames with sequence numbers and case rules, then export a CSV plan.
Battery Life Calculator

Capacity ÷ load × efficiency = runtime — mAh and Wh modes, reverse-solve capacity, charge time, share link — browser-only
BBCode to HTML Converter

Paste forum BBCode, get safe HTML — live preview, escaped output, one-click copy, all in your browser
BCD Converter

Decimal ⇄ binary coded decimal in 8421 code, with packed view, hex and per-digit nibbles, all in your browser
Bcrypt Generator

bcrypt password hash generator + verifier — pick rounds, hash and compare in browser.
Beaufort Cipher

C = (key − text) mod 26, reciprocal — one keyword both encrypts and decrypts — browser-only
BEM Class Name Generator

Build block__element--modifier the right way, normalized to kebab-case, with HTML and SCSS nesting examples, browser-only
Binary Calculator

Add, subtract, multiply and divide two binary numbers, exact BigInt math, results in binary, decimal, hex and octal, browser-only
Bit Shift Calculator

Left shift, logical and arithmetic right shift — see the bits move, pick 8/16/32-bit, read decimal, hex and binary — browser-only
Bitwise Calculator

AND, OR, XOR, NOT and bit shifts on integers, with decimal, hex and binary side by side, all in your browser
CSS Border Radius Generator

Border radius generator — independent 8-corner control + blob shape randomizer, live preview, copy CSS or SVG path.
CSS Box Shadow Generator

Visual CSS box-shadow builder — multi-layer, inset, color/blur with live preview.
CSS Design Token Contrast Matrix

Paste CSS variables or JSON tokens, select fg/bg pairs, and flag every WCAG AA/AAA failure across your design system at once.
JWT Decoder and Claims Inspector

Decode JWT headers and payloads locally, inspect registered claims, timing, audience and risk signals.
Business Days Calculator

Working days between two dates, or a date N working days out — weekends + holidays excluded, browser-only
Cache-Control Builder

Tick the directives, set the lifetime, copy a correct Cache-Control header plus Nginx and Apache lines
Caesar Cipher Encoder & Decoder

Encrypt, decrypt and brute-force a Caesar shift cipher — all 25 shifts at once, ROT13 shortcut, browser-only
Capacitor Code Calculator

Read a 3-digit capacitor code both ways: 104 to 100 nF, or a value back to its code, with pF / nF / µF and tolerance letters, browser-only
Capacitor Energy Calculator

E = ½CV² stored energy + charge Q = CV — solve any one of C, V, E from the other two — browser-only
Case Converter

Convert text between camelCase, snake_case, kebab-case, PascalCase, Title Case, UPPER, lower — instant, browser-only
Character Frequency Counter

Count how often every character appears, ranked by frequency, with case, space and punctuation toggles, browser-only
Chinese Pinyin Converter

Chinese characters to pinyin — with tone marks or numbers, supports simplified and traditional.
CSS Clip-Path Generator

Visual CSS clip-path builder — polygon, circle, ellipse, inset with drag handles.
Cloudflare DNS Cheatsheet

Cloudflare DNS cheat sheet with proxy rules, TTL notes, CNAME flattening, mail records, and a local record checker
Code Screenshot Generator

Code screenshot generator (Carbon-like) — syntax highlight, beautiful gradient backgrounds, window chrome, export PNG/SVG for X / blog covers.
Collatz Conjecture Calculator

Enter any positive integer, watch 3n+1 run to 1 — full hailstone sequence, stopping time, and peak, exact via BigInt
Color Blindness Simulator

Color blindness simulator — paste hex or upload image, see how it looks to people with protanopia / deuteranopia / tritanopia / monochromacy.
Color Contrast Checker

Color contrast checker — WCAG 2.2 AA/AAA compliance for normal/large text, real-time grade.
Color Converter

HEX ⇄ RGB ⇄ HSL ⇄ HSV ⇄ CMYK — instant 5-way conversion, live swatch — browser-only
Color Shades Generator

Turn one base color into a Tailwind-style 50–950 tint & shade scale — copy each step, export to Tailwind / CSS / SCSS / JSON — browser-only
Column Align

Pad delimited rows into an even monospace grid, like column -t, with correct CJK width — browser-only
Columnar Transposition Cipher

Keyword sets the column order, the grid does the scrambling — encrypt, decrypt, regular or irregular padding, all in your browser
Common Ports Reference

TCP/UDP port cheat sheet, 60+ services, search by number or name, copy in one click, browser-only
Continued Fraction Calculator

Expand a decimal or fraction into a continued fraction [a0;a1,a2,...] with the convergents that best approximate it — browser-only
Conventional Commit Generator

Build a spec-perfect commit line from a type, scope, and one-line summary, with live validation and footers
Coordinate Converter

Convert GPS coordinates between DMS, decimal degrees and decimal minutes, paste straight into Google Maps, all in your browser
Coordinate Distance Calculator

Great-circle distance between two lat/long points with the Haversine formula, plus bearing and midpoint, all in your browser
CORS Header Generator

Pick an origin, methods and headers, get Access-Control-* response headers as a raw list, Nginx, Apache or Express code
Cover Letter Generator

Cover letter generator — fill 6 fields, pick a tone, get a tailored cover letter in 4 templates, bilingual.
CRC32 Checksum Calculator

Standard CRC-32 (IEEE) of any text in hex and unsigned decimal, with optional CRC32C, computed in your browser
Tailwind Palette Contrast Matrix

Paste Tailwind colors, CSS theme tokens, or JSON palettes and audit every foreground/background pair for WCAG AA and AAA contrast.
Credit Card Number Deduplicator

Find duplicates and keep one clean copy of credit card numbers from pasted text or uploaded local files.
Credit Card Number Extractor

Extract, dedupe, and export credit card numbers from pasted text or uploaded local files.
Credit Card Number List Converter

Convert credit card numbers from pasted text or uploaded local files.
Credit Card Number List Validator

Validate and explain issues in credit card numbers from pasted text or uploaded local files.
Credit Card Number Normalizer

Normalize, sort, and prepare credit card numbers from pasted text or uploaded local files.
Test Credit Card Number Generator

Luhn-valid fake card numbers for payment-integration testing — Visa, Mastercard, Amex, Discover, JCB, Diners — non-real, sandbox-only — browser-side
Credit Card Type Detector

Read the card network from a number's BIN prefix — Visa, Mastercard, Amex, Discover, JCB, Diners, UnionPay — plus Luhn check, 100% in your browser
Cron Cheatsheet

Cron cheat sheet — 80+ entries covering syntax, time expressions, special strings, environment variables, crontab management, and common pitfalls.
Cron Expression Explainer — Decode Any Cron + Next 20 Runs

Cron expression explainer — paste any cron, get plain English/Chinese + next 20 runs + visual time grid.
Crontab Helper — Visual Builder & Explainer

Visual crontab builder + human-readable explanation + next run preview.
CSP Generator

Build a Content-Security-Policy from directive toggles, get the header line, meta tag and Nginx snippet, with live unsafe-inline warnings, browser-only
CSP Policy Auditor

Inspect Content-Security-Policy directives for unsafe sources, missing fallbacks, framing gaps, object-src, base-uri, and reporting coverage.
CSS Button Generator

Design buttons that look pressable — 3D raised, neumorphic, glass — with a live preview you can hover & press, plus full :hover/:active CSS export
CSS clamp() Fluid Typography Generator

CSS clamp() fluid typography generator — min/max font size, viewport range, full type scale (h1-h6 + body), copy CSS / Tailwind.
CSS Color Format Converter

Convert any color between HEX, RGB, HSL, OKLCH, CSS variable, and Tailwind — with live preview.
CSS Cubic Bezier Generator

Drag two handles, read the cubic-bezier() — five built-in presets, motion preview, solve y for any progress, browser-only
CSS Filter Generator

Dial in blur, brightness, contrast, grayscale, sepia, hue-rotate, saturate, invert, opacity + drop-shadow with live preview — copy the filter string
CSS Flexbox Generator

Generate production-ready flexbox CSS from visual controls — pick a layout preset, tweak properties, copy CSS, Tailwind, or React inline styles in one click.
CSS Flexbox Playground

Visual CSS Flexbox sandbox — tweak container and item properties live, see the layout update instantly, copy ready-to-use CSS.
CSS Font Stack Generator

CSS font stack generator — system-safe font families with full Win/Mac/Linux/Android/iOS fallback chains, with CJK fallbacks, copy as CSS/Tailwind/SwiftUI.
CSS Formatter & Minifier

Format and beautify CSS — sort properties, indent rules, expand or minify.
CSS Grid Visual Generator

CSS grid visual generator — drag to set columns/rows, place grid-area named regions, copy ready CSS + HTML, with 12 layout templates.
CSS Grid Generator

CSS Grid generator — visually design grid layouts (rows/cols/gap/areas), copy CSS code, fully responsive.
CSS Keyframes Animation Generator

Visually build @keyframes — edit keyframes, set transform/opacity/color, live-preview, and copy production-ready CSS — browser-only
CSS Line Clamp Generator

Truncate text after N lines with a trailing ellipsis, copy the CSS and the Tailwind class, with live preview, browser-only
CSS Loaders Generator

CSS loaders — 40+ pure-CSS spinners/skeletons, customize color/size/speed, copy ready-to-use code.
CSS Media Query Generator

CSS @media query + responsive breakpoint generator — Tailwind / Bootstrap / Material presets, mobile-first vs desktop-first, dark mode, hover, reduced-motion, aspect-ratio.
CSS Minifier

Minify CSS — strip comments, whitespace, shorten colors, merge selectors. 30-60% smaller.
CSS Scrollbar Generator

Design custom scrollbars visually — exports WebKit + Firefox-standard CSS, live preview, one-click copy — browser-only
CSS Shadow Generator Pro

CSS shadow generator pro — multi-layer box-shadow + text-shadow + filter:drop-shadow, with Material/Tailwind/Apple shadow presets and dark-mode preview.
CSS Specificity Calculator

Score any CSS selector as an (a, b, c) triple, compare which rule wins the cascade, and see exactly which digit decided it — browser-only
CSS Text Shadow Generator

Visual CSS text-shadow builder — multi-layer, color, blur with live preview and shareable links.
CSS to Style Object

Paste CSS declarations, get a React inline style object — kebab keys camelCased, vendor prefixes handled, optional bare numbers, browser-only
CSS Transform Generator

CSS transform generator — rotate/scale/skew/translate (2D + 3D) with live preview, copy CSS, 12 preset combos.
CSS Triangle Generator

Pure-CSS triangles via the border trick — 8 directions, live preview, copy both border + clip-path CSS — browser-only
CSS Variable Deduplicator

Find duplicates and keep one clean copy of css variables from pasted text or uploaded local files.
CSS Variable Extractor

Extract, dedupe, and export css variables from pasted text or uploaded local files.
CSS Variable List Converter

Convert css variables from pasted text or uploaded local files.
CSS Variable List Validator

Validate and explain issues in css variables from pasted text or uploaded local files.
CSS Variable Normalizer

Normalize, sort, and prepare css variables from pasted text or uploaded local files.
CSV Column Extractor

Upload or paste CSV, keep only selected columns by name or index, and export a smaller privacy-safe file.
CSV Data Quality Profiler

Upload CSV or TSV and profile missing values, inferred types, invalid cells, duplicate rows, whitespace issues, top values, and numeric outliers.
CSV Deduplicator

Remove duplicate CSV rows by full row or selected key columns from uploaded files, locally and safely.
CSV Filter

Filter uploaded CSV rows by column value using contains, equals, or regex, with local browser processing.
CSV Header Normalizer

Standardize CSV header rows to snake_case, kebab-case, camelCase, or Title Case before imports and scripts.
CSV Sorter

Sort uploaded CSV rows by a selected column with numeric-aware ordering and local-only processing.
CSV Stats Summary

Upload CSV and get a quick Markdown profile of filled, missing, unique, numeric, min, max, and average values.
CSV to HTML Table

Paste CSV, get a clean HTML table, with header toggle, optional class and inline borders, all in your browser
CSV ⇄ JSON Converter

Convert CSV to JSON or JSON to CSV — handles quoted commas, newlines in cells, custom delimiter — browser-only
CSV to LaTeX Table

Paste CSV, get a compile-ready LaTeX tabular with booktabs, l/c/r alignment, a table environment and safe escaping, all in your browser
CSV to Markdown Table

Convert uploaded or pasted CSV into clean Markdown tables with quoted-cell support, locally in the browser.
CSV to SQL Converter

Turn CSV into CREATE TABLE + INSERT statements — type inference, safe value escaping, MySQL / PostgreSQL / SQLite — browser-only
CSV to TSV Converter

Convert CSV files to tab-separated values while preserving quoted commas, quotes, and multiline cells locally.
CSV to XML Converter

Turn a CSV table into clean, indented XML — name the root and row elements, columns as elements or attributes, escaped output. Browser-only.
CSV to YAML Converter

Turn a spreadsheet export into a clean YAML array of objects — RFC 4180 quoting, optional type inference, browser-only
CSV Transposer

Flip CSV rows and columns from uploaded files or pasted data, with ragged-row handling and local output.
Cubic Bezier Editor

CSS cubic-bezier editor — drag two control points, preview live with bouncing ball + scaling box + opacity fade, copy CSS / JS / Framer Motion / GSAP / SVG path.
curl Cheatsheet

curl cheat sheet — 80+ curl commands for GET/POST/auth/upload/download/SSL/proxy, with real examples and pitfalls.
curl to Code Converter

Paste a curl command, get JS fetch / Python requests / Node axios / PHP cURL / Go net/http — parsed locally, instant
Data Storage Converter

Convert bytes, KB, MB, GB, TB and bits — decimal (1000) and binary (1024, KiB/MiB/GiB) side by side, with the hard-drive 931 GiB gotcha explained — browser-only
Data Transfer Rate Converter

bps / Kbps / Mbps / Gbps ⇄ B/s, KB/s, MB/s — bit-rate vs byte-rate, 8x apart — browser-only
Decibel Calculator

Add sound levels, convert ratio ⇄ dB (power 10·log, amplitude 20·log), and read a common-sound reference table — browser-only
Diceware Passphrase Generator

Cryptographically secure word-based passphrases — pick word count, separator, casing; live entropy; 100% in-browser, never in the URL.
Directory Tree Generator

Turn an indented file list into a clean ASCII folder tree with box-drawing guides, choose Unicode or ASCII, then copy it into any README, browser-only
DNA to RNA Converter

Transcribe DNA to mRNA, build the reverse complement, translate codons to protein — standard genetic code, browser-only
DNS Record Explainer

DNS record explainer — all 18 common record types (A, AAAA, CNAME, MX, TXT, SRV, etc.) with syntax, examples, and gotchas.
Docker Cheatsheet

Docker command cheat sheet — 80+ commands with real examples, common mistakes, and Compose section.
Domain Name Deduplicator

Find duplicates and keep one clean copy of domain names from pasted text or uploaded local files.
Domain Name Extractor

Extract, dedupe, and export domain names from pasted text or uploaded local files.
Domain Name List Converter

Convert domain names from pasted text or uploaded local files.
Domain Name List Validator

Validate and explain issues in domain names from pasted text or uploaded local files.
Domain Name Normalizer

Normalize, sort, and prepare domain names from pasted text or uploaded local files.
.env File Validator

.env file validator — parse Bash-style .env, detect dups / missing required / unsafe values / leaked secret patterns; cross-compare prod / staging / dev envs.
Download Time Calculator

How long to download a file at a given speed, plus reverse-solve the bandwidth a deadline needs, with the 8-bits-per-byte trap handled, browser-only
Duplicate File Finder

Upload a batch and find exact duplicate files by SHA hash locally, with a Markdown cleanup report.
Duration Converter

Seconds ⇄ minutes ⇄ hours ⇄ days ⇄ weeks, plus human-readable, ISO 8601 duration and HH:MM:SS — one input, every format — browser-only
Duration Humanizer

Milliseconds or seconds into 2d 3h 5m 10s, 2 days 3 hours, and 3 hours ago, bilingual, copy in one click, browser-only
EAN / UPC Check Digit Calculator

Compute or verify the check digit for EAN-13, UPC-A and EAN-8 barcodes, mod-10 weighting with the odd and even positions, browser-only
.editorconfig Generator

Visual .editorconfig builder — indent, charset, line endings, trailing whitespace, per-glob overrides — browser-only
Elasticsearch Cheatsheet

Elasticsearch cheat sheet — 80+ Query DSL, mapping, analyzer, aggregation, replication, with real examples.
Email Address Deduplicator

Find duplicates and keep one clean copy of email addresses from pasted text or uploaded local files.
Email Address Extractor

Extract, dedupe, and export email addresses from pasted text or uploaded local files.
Email Address List Converter

Convert email addresses from pasted text or uploaded local files.
Email Address List Validator

Validate and explain issues in email addresses from pasted text or uploaded local files.
Email Address Normalizer

Normalize, sort, and prepare email addresses from pasted text or uploaded local files.
Email Obfuscator

Hide your email from scraper bots — HTML entities, [at]/[dot] text, ROT13+JS link — browser-only, one-click copy
Email Signature Generator

Fill in your details, pick a template, get table-based inline-style HTML that pastes cleanly into Gmail and Outlook — 100% browser-only
Email Validator

Validate emails — RFC 5321 syntax + bulk paste + disposable detection + MX hint.
Emoji Remover

Strip every emoji from text, family and skin-tone combos removed whole, your words and punctuation left untouched, browser-only
Emoji to Unicode Converter

Emoji ⇄ Unicode code points, both ways. U+XXXX, decimal, HTML entity, JS and CSS escapes, every code point of a ZWJ family, skin tone or flag, plus one-click restore, all in your browser
Engineering Notation Converter

Plain number ⇄ engineering notation (×10³ⁿ) ⇄ SI prefix (47kΩ) — exponent always a multiple of 3, with scientific notation for contrast — browser-only
ENV Secret Scanner

Scan .env files, config snippets, and CI logs locally for likely API keys, tokens, private keys, JWTs, and database URLs.
.env to JSON Converter

Convert .env environment variables to JSON and back, with quote escaping, export prefix, and optional type inference, all in your browser
Environment Variable Deduplicator

Find duplicates and keep one clean copy of environment variables from pasted text or uploaded local files.
Environment Variable Extractor

Extract, dedupe, and export environment variables from pasted text or uploaded local files.
Environment Variable List Converter

Convert environment variables from pasted text or uploaded local files.
Environment Variable List Validator

Validate and explain issues in environment variables from pasted text or uploaded local files.
Environment Variable Normalizer

Normalize, sort, and prepare environment variables from pasted text or uploaded local files.
Excel Column Converter

Turn column letters into numbers and back: A is 1, Z is 26, AA is 27, batch convert, paste A1 refs, copy in one click, all in your browser
Factorial Calculator

Exact n! for any non-negative integer, with digit count, trailing zeros, double factorial and scientific notation, computed on BigInt right in your browser
Favicon Generator

Generate favicon set — text or upload, output 16x16 / 32x32 / 180x180 / 512x512 PNG.
Fibonacci Generator

First N terms, a range, or the nth value, with running sum and golden-ratio convergence, exact via BigInt, all in your browser
Figlet ASCII Banner Generator

Turn a short word into a big ASCII letter banner with three built-in fonts, all in your browser
File Checksum Compare

Paste an expected checksum, upload a file, and verify SHA digest matches locally before installing or sharing.
File Hash Calculator

Compute SHA-1, SHA-256, SHA-384, or SHA-512 hashes for uploaded files entirely in the browser.
File MIME Type Inspector

Upload files and inspect filename, size, browser MIME type, extension, and magic-byte signature locally.
File to Base64 Converter

Upload a small file and convert it to raw Base64 or a data URL locally for embeds, fixtures, and tests.
Filename Sanitizer

Strip illegal characters and make any string a safe cross-platform filename, in your browser
Find and Replace Text

Batch find-and-replace on big text — regex, $1 capture groups, whole-word, case toggle, multiple chained rules — runs entirely in your browser
Flexbox Playground & CSS Generator

Flexbox playground — toggle every container and item property on a real flex box and copy the exact CSS. direction, justify, align, gap, order, grow/shrink/basis, align-self. 100% client-side.
Font File Inspector

Upload TTF or OTF files and extract family names, PostScript names, version, units per em, glyph count, and table list.
Frequency Wavelength Calculator

Convert frequency to wavelength and back with λ = v/f, pick the wave speed, read the EM spectrum band, copy in one click, browser-only
GC Content Calculator

Paste a DNA or RNA sequence and get GC%, AT%, per-base counts, length and a melting-temperature estimate. FASTA headers and spaces are ignored, invalid bases flagged, all in your browser.
Geohash Converter

Latitude/longitude ⇄ geohash, base32, precision 1-12, bounding box and 8 neighbors, all in your browser
Git Cheatsheet

Git command cheat sheet — searchable, with explanations, common mistakes, and real examples.
GitHub README Badge Generator

GitHub README badge generator — shields.io-style badges, 50+ presets (build/version/license/coverage/etc), custom labels, copy as Markdown/HTML/AsciiDoc/RST.
.gitignore Generator

Pick your stack — Node, Python, Go, Docker, macOS, VS Code — and get a deduped, sectioned .gitignore. Browser-only.
GitLab CI Cheatsheet

GitLab CI/CD cheat sheet — 80+ entries covering pipeline structure, job config, rules, variables, artifacts, runners, templates, security, and the GitLab API.
Glassmorphism Generator

Glassmorphism CSS generator — backdrop-filter blur + transparency + border, live preview with 8 background presets, copy CSS/Tailwind/SwiftUI.
Glob Pattern Tester

Test which paths a glob matches — supports * ** ? [a-z] {js,ts} and ! — see the equivalent regex — browser-only
Go (Golang) Cheatsheet

Go (Golang) cheat sheet — 100+ idiomatic snippets covering syntax, goroutines, channels, generics, errors, stdlib.
CSS Gradient Generator

Visual CSS gradient builder — linear, radial, conic with multi-stop colors, live preview, copy CSS, PNG export.
GraphQL Formatter & Minifier

GraphQL formatter + minifier — beautify query/mutation/subscription/schema, validate syntax, copy minified single-line for HTTP body.
Gray Code Converter

Decimal, binary and Gray code three ways, gray = n^(n>>1), one click each side, all in your browser
gron Converter (JSON to gron / ungron)

Make JSON greppable. json.users[0].name = "Ada"; one leaf per line, and ungron right back. Runs in your browser.
Hamming Code Calculator

Encode, decode and error-correct Hamming (SEC / SECDED) codes — syndrome, parity coverage, one-click copy — browser-only
Hamming Distance Calculator

Count the differing positions between two equal-length inputs, in characters, binary bits or integer XOR, all in your browser
Happy Number Checker

Replace N with the sum of its squared digits — reach 1 and it is happy, hit the 4-cycle and it is not. See every step.
HAR Performance Analyzer

Upload a Chrome DevTools HAR file and get a local performance, cache, host, asset, status, and security-header report.
Hash Type Detector

Paste any hash string and instantly identify MD5, SHA-256, bcrypt, Argon2, and 30+ other formats
Hex Color Deduplicator

Find duplicates and keep one clean copy of hex colors from pasted text or uploaded local files.
Hex Color Extractor

Extract, dedupe, and export hex colors from pasted text or uploaded local files.
Hex Color List Converter

Convert hex colors from pasted text or uploaded local files.
Hex Color List Validator

Validate and explain issues in hex colors from pasted text or uploaded local files.
Hex Color Normalizer

Normalize, sort, and prepare hex colors from pasted text or uploaded local files.
Hex Dump Viewer

Offset, hex bytes and ASCII side by side, the classic xxd / hexdump -C layout, fully in your browser
HMAC Generator

HMAC-SHA1/256/384/512 — message + secret key, output in hex and base64, key read as UTF-8/hex/base64 — 100% in-browser
Horsepower Torque Calculator

Solve any one of horsepower, torque or RPM from the other two — HP = T × RPM / 5252, HP↔kW and lb·ft↔N·m built in — browser-only
Hreflang Tag Generator

Paste lang|url pairs, get hreflang link tags, HTTP Link header and sitemap XML with x-default and code validation, browser-only
.htaccess Generator

Generate Apache .htaccess — HTTPS redirect, www toggle, gzip, cache headers, hotlink protection.
HTML Color Names

HTML named colors — all 147 CSS color names with hex/RGB/HSL, searchable + sortable.
HTML Entities Encoder

Encode/decode HTML entities — & < > " ' and all numeric refs — browser-only
HTML Entity Encoder / Decoder

Encode & decode all HTML5 entities — named, decimal, hex — XSS prevention and safe markup, 100% client-side
HTML Form Extractor

Upload or paste HTML and extract forms, methods, actions, fields, labels, required flags, autocomplete, password fields, and security risks.
HTML Formatter

Beautify minified or messy HTML into clean indented markup, browser-only
HTML Link Extractor

Upload HTML and extract anchors, images, scripts, stylesheets, canonicals, and meta URLs into CSV locally.
HTML Minifier

Minify HTML — strip comments, whitespace, optional attributes, inline CSS/JS. 40-60% smaller.
HTML Table Generator

Build an HTML table visually — rows/columns, header cells, alignment, borders, zebra stripes, paste CSV/TSV — copy clean markup, browser-only
HTML Table to CSV Converter

HTML table to CSV converter — paste HTML or full page source, extract all tables, get CSV/TSV/JSON/Excel-ready output with header detection + colspan/rowspan handling.
HTML Table to JSON

Paste an HTML <table>, get clean JSON, array of objects or 2D array, type inference, browser-only
HTML Table to Markdown

Paste an HTML table, get a clean GitHub-flavoured Markdown table with the |---| separator row, tags stripped, entities decoded and pipes escaped, all in your browser
HTML to JSX

Paste HTML, get React-ready JSX — class becomes className, inline styles become objects, tags self-close. Browser-only.
HTML to Markdown

HTML to Markdown — paste rich content, get clean .md with links, code, tables, lists preserved.
.htpasswd Generator

Generate Apache/Nginx .htpasswd lines — bcrypt, apr1 (MD5), SHA-1 — multi-user, copy, download — 100% browser-only
HTTP Header Deduplicator

Find duplicates and keep one clean copy of http headers from pasted text or uploaded local files.
HTTP Header Extractor

Extract, dedupe, and export http headers from pasted text or uploaded local files.
HTTP Header List Converter

Convert http headers from pasted text or uploaded local files.
HTTP Header List Validator

Validate and explain issues in http headers from pasted text or uploaded local files.
HTTP Header Normalizer

Normalize, sort, and prepare http headers from pasted text or uploaded local files.
HTTP Header Parser

Paste raw HTTP headers, get a clean table with per-header meaning, duplicate and security badges, browser-only
HTTP Security Header Auditor

Audit raw response headers for HSTS, CSP, cookie flags, MIME sniffing, clickjacking, referrer, and permissions policy gaps.
HTTP Status Code Reference

Every HTTP status code 1xx to 5xx with meaning, when-to-use and RFC, search by code or keyword, browser-only
HTTP Status Code Explorer

HTTP status code explorer — all 70+ codes with meaning, common causes, real examples, and what to check.
Google Fonts CSS2 URL Builder

Parse, edit, and generate Google Fonts CSS2 links, HTML preconnect tags, @import CSS, variables, and Tailwind font stacks.
IBAN Validator

Check any IBAN with the ISO 7064 mod-97 checksum and a 60-country length table, formatted output, one-click copy, browser-only
IEEE 754 Floating Point Converter

Decimal to single and double precision bits, sign exponent mantissa split, full hex and binary, all in your browser
Image Compressor (Local)

Image compressor — squeeze JPG/PNG/WebP without server upload, with quality slider, batch mode, file size comparison.
Image Format Converter

Image format converter — JPG ↔ PNG ↔ WebP ↔ AVIF, batch + transparent background handling, 100% client-side.
Image Host

Upload an image, get a permanent direct link plus ready-to-paste Markdown, HTML and BBCode.
Image Metadata Inspector

Inspect PNG, JPEG, GIF, WebP, and SVG dimensions, bit depth, ICC, EXIF, XMP, animation, and notes.
Image Resizer

Image resizer — resize JPG/PNG/WebP by pixels/%/preset, fully client-side, no upload.
Image Target Size Compressor

Compress one image to a target KB size locally with quality search, automatic downscaling, preview, and download.
Image to ASCII Art

Image to ASCII art — convert any image to text-based art with adjustable density and character set.
Image to PDF

Image to PDF — combine JPG, PNG & WebP into one PDF, drag to reorder, pick A4/Letter/fit-to-image, 100% in your browser.
INI Formatter & Validator

Format and validate INI / TOML-like config — sort sections, align equal signs.
INI to JSON Converter

Turn INI / .cfg / .conf into JSON and back, with section nesting, comment stripping and optional type inference, all in your browser
Interview Questions Bank

Interview questions bank — 300+ real questions across behavioral / technical / case / culture, with strong answer frameworks.
IP Subnet Calculator (CIDR)

Type an IPv4 CIDR and get network, broadcast, host range, mask, wildcard, class and subnet splits — browser-only.
IP to Decimal Converter

IPv4 dotted-quad to 32-bit integer, binary and hex, both directions, browser-only
IPv4 Address Deduplicator

Find duplicates and keep one clean copy of ipv4 addresses from pasted text or uploaded local files.
IPv4 Address Extractor

Extract, dedupe, and export ipv4 addresses from pasted text or uploaded local files.
IPv4 Address List Converter

Convert ipv4 addresses from pasted text or uploaded local files.
IPv4 Address List Validator

Validate and explain issues in ipv4 addresses from pasted text or uploaded local files.
IPv4 Address Normalizer

Normalize, sort, and prepare ipv4 addresses from pasted text or uploaded local files.
IPv6 Address Deduplicator

Find duplicates and keep one clean copy of ipv6 addresses from pasted text or uploaded local files.
IPv6 Address Extractor

Extract, dedupe, and export ipv6 addresses from pasted text or uploaded local files.
IPv6 Address List Converter

Convert ipv6 addresses from pasted text or uploaded local files.
IPv6 Address List Validator

Validate and explain issues in ipv6 addresses from pasted text or uploaded local files.
IPv6 Address Normalizer

Normalize, sort, and prepare ipv6 addresses from pasted text or uploaded local files.
ISBN-10 to ISBN-13 Converter

Convert ISBN-10 ⇄ ISBN-13 with the check digit recomputed — 978 prefix, mod-10 and mod-11, hyphen-aware, browser-only
ISBN Validator

Check an ISBN-10 or ISBN-13 check digit and convert between the two, with the X case and 978 prefix handled, all in your browser
ISO Date Deduplicator

Find duplicates and keep one clean copy of iso dates from pasted text or uploaded local files.
ISO Date Extractor

Extract, dedupe, and export iso dates from pasted text or uploaded local files.
ISO Date List Converter

Convert iso dates from pasted text or uploaded local files.
ISO Date List Validator

Validate and explain issues in iso dates from pasted text or uploaded local files.
ISO Date Normalizer

Normalize, sort, and prepare iso dates from pasted text or uploaded local files.
ISSN Validator

Check an 8-digit journal ISSN with the MOD 11 check digit — single or batch, computes the check character, one-click copy, browser-only
JavaScript String Escaper

Escape and unescape strings for JSON, regex literals, and template literals — browser-only, instant output
JS Minifier

Minify JavaScript — strip comments, whitespace, optional name shortening. 40-70% smaller.
JS Obfuscator

Lightly obfuscate JavaScript in the browser: strip comments, remove debugger/console calls, and optionally wrap strings with base64.
JS Object to JSON

Paste a JS object literal or JSON5, get strict JSON: quote bare keys, swap single quotes, strip comments and trailing commas, runs in your browser
JSON Diff

Structural JSON compare — added / removed / changed keys by path, three-colour tree, browser-only
JSON Flatten / Unflatten

Flatten nested JSON to dot-notation keys and unflatten it back — choose the delimiter and array style, types preserved, browser-only.
JSON Formatter & Validator

Format, validate, and minify JSON instantly — right in your browser.
JSON-LD Schema Generator

Build valid schema.org JSON-LD for Article, Product, FAQ, LocalBusiness, Event and more, copy the script tag, drop it in your head
JSON Lines Formatter

Validate JSONL line by line, pretty-print it, convert to a JSON array, or export a CSV-like table locally.
JSON Merge

Deep-merge two or more JSON objects in the browser, with array strategy and prototype-pollution guard
JSON Minifier

Minify JSON into a compact single line, optionally sort object keys, and keep everything local.
JSON Schema Generator

Paste a JSON sample, get a typed JSON Schema (draft-07 or 2020-12) in your browser
JSON Schema Inferencer

Paste JSON or NDJSON samples and infer a Draft 2020-12 style schema with types, required fields, formats, enums, and examples.
JSON Sort Keys

Sort JSON object keys alphabetically, recurse into nested objects, asc or desc, values untouched, runs in your browser
JSON String Escape and Unescape Tool for Developers

Escape raw text into JSON string content or a quoted JSON string literal, and decode escaped JSON strings back to readable text in your browser.
JSON to C# Class

JSON to C# class or record — paste JSON, get PascalCase properties with System.Text.Json or Newtonsoft attributes, nested classes, nullable T?, init setters, DateTime detection.
JSON to CSV Converter

Turn a JSON array (or object) into clean CSV — flattens nested keys, escapes per RFC 4180, custom delimiter, UTF-8 BOM for Excel — browser-only
JSON to Dart Class

JSON to Dart / Flutter class — paste JSON, get final fields, camelCase names, factory fromJson, toJson, null-safe T?, nested classes, and optional @JsonSerializable codegen.
JSON to Go Struct

JSON to Go struct — paste JSON, get typed structs with json tags, exported fields, nested sub-structs, pointers for nullable, int64 and omitempty options.
JSON to Java Class

JSON to Java POJO, record, or Lombok @Data — paste JSON, get camelCase fields with getters/setters, Jackson @JsonProperty or Gson @SerializedName, nested classes, primitive vs boxed inference.
JSON to Kotlin Data Class

JSON to Kotlin data class — paste JSON, get val properties, camelCase fields, nullable T?, nested classes, and kotlinx.serialization @SerialName, Gson @SerializedName, or Moshi @Json annotations.
JSON to Markdown Table

Paste a JSON array of objects, get a clean GitHub-flavored Markdown table. Key union, pipe escaping, alignment, all in your browser.
JSON to Mongoose Schema

Paste a JSON document, get a typed mongoose.Schema with the model export, nested sub-schemas, date detection, browser-only
JSON to NDJSON Converter

JSON array to NDJSON and back, one compact JSON value per line, with bad-line numbers and pick-your-indent, all in your browser
JSON to PHP Array

JSON to PHP array — paste JSON, get a clean associative or indexed array with short [] or array() syntax, 2/4 indent, trailing comma, and an optional <?php return …; wrapper.
JSON to Protobuf

JSON to Protobuf — paste JSON, get proto3 message definitions with inferred scalar types, incrementing field numbers, snake_case fields, repeated arrays, and named nested messages.
JSON to Pydantic

Paste JSON, get Pydantic BaseModel classes with type hints, nested sub-models, List[T], Optional inference, v1 / v2 and aliases.
JSON to Python Dataclass

JSON to Python — paste JSON, get @dataclass or Pydantic v2 models with type hints, Optional inference, nested classes, snake_case fields and aliases.
JSON to Query String Converter

Turn a JSON object into a URL query string — repeat, key[], or comma arrays, bracket-nested objects, sorted, skip-empty — and back to JSON, 100% in your browser
JSON to Ruby

Paste JSON, get a Ruby Hash literal or Struct.new classes; symbol or string keys, null maps to nil, nested objects, zero upload.
JSON to Rust Struct

JSON to Rust struct — paste JSON, get serde-derived structs with snake_case fields, serde rename, Option for nullable, Vec for arrays, nested sub-structs.
JSON to Scala

Paste JSON, get Scala case classes. Nested objects become child classes, arrays become List, null becomes Option, all in your browser.
JSON to SQL Converter

Turn a JSON array into ready-to-run INSERT statements, MySQL / PostgreSQL / SQLite dialects, browser-only
JSON to Swift Codable

JSON to Swift Codable — paste JSON, get struct or class types conforming to Codable, camelCase properties, a CodingKeys enum for non-matching keys, Optional T? for nullable fields, and nested types.
JSON to TOML Converter

Paste JSON, get clean TOML with proper tables and arrays of tables, all in your browser
JSON to TSV Converter

Turn a JSON array into tab-separated values you can paste straight into Excel or Google Sheets, with header toggle and safe escaping, all in your browser
JSON to TypeScript Interface

JSON to TypeScript interface — paste JSON, get clean interfaces with union types from arrays, optional vs required detection, root name customizable.
JSON to XML Converter

Convert JSON to clean, indented XML — @attr/#text conventions, custom root, escaped output. Browser-only.
JSON to YAML Converter

Convert JSON to clean YAML — block scalars for multiline strings, optional key sorting, 2/4-space indent, line-numbered errors — browser-only
JSONL to JSON Converter

Turn newline-delimited JSON into a JSON array and back, with bad-line numbers and pick-your-indent — browser only
JSONPath / JMESPath Query Tester

JSONPath / JMESPath query tester — paste JSON, write a path, see matched values + matched paths highlighted live.
Julian Date Converter

Gregorian date ⇄ Julian Day Number (JDN), fractional JD, Modified Julian Date (MJD) and ordinal day-of-year — astronomy-grade, browser-only
JWT Decoder

Decode JWT header / payload / signature — verify structure, check exp, copy claims — browser-only
JWT Encoder

Encode JWT — pick algorithm (HS256/HS384/HS512), set header/payload/secret, get token.
JWT Token Deduplicator

Find duplicates and keep one clean copy of jwt tokens from pasted text or uploaded local files.
JWT Token Extractor

Extract, dedupe, and export jwt tokens from pasted text or uploaded local files.
JWT Token List Converter

Convert jwt tokens from pasted text or uploaded local files.
JWT Token List Validator

Validate and explain issues in jwt tokens from pasted text or uploaded local files.
JWT Token Normalizer

Normalize, sort, and prepare jwt tokens from pasted text or uploaded local files.
kubectl Cheatsheet

kubectl cheat sheet — 100+ Kubernetes commands with real examples, common pitfalls, and YAML snippets.
LC Resonance Frequency Calculator

f = 1 / (2π·√(L·C)) — frequency from L and C, or solve back for the capacitor or inductor — angular frequency, one-click copy, browser-only
LED Resistor Calculator

R =(Vs − n·Vf)/ If, with nearest E12/E24 value, resistor wattage and a dark-LED check, browser-only
LED Strip Power Calculator

W/m × length = total watts · watts ÷ volts = amps · +20% headroom sizes the supply · 5V / 12V / 24V · browser-only
Open Source License Generator

Pick MIT, Apache, BSD, GPL and 4 more, fill in your name and year, get a ready-to-save LICENSE file. Browser-only.
Linux Permission (chmod) Calculator

Linux permission (chmod) calculator — convert between octal (755), symbolic (rwxr-xr-x), and ls -l forms, with safety warnings.
List Comparison

Compare two lists line by line: only in A, only in B, in both, and merged — all in your browser
List to Comma Separated

Turn a column of lines into a comma-separated string — add quotes, prefix/suffix, dedupe, sort, or split it back — browser-only
List to JSON Array

Turn a column of lines into a JSON array, with type inference, dedupe and pretty print, and split it back to lines, all in your browser
LLM Pricing Calculator

Estimate daily and monthly LLM spend from tokens, request volume, and editable model prices.
Local File Workbench

Triage a mixed batch locally for file type mismatches, duplicate candidates, metadata privacy, archive risks, and next-step tools.
Log Error Analyzer

Paste logs and group repeated errors, warnings, stack traces, HTTP statuses, endpoint patterns, and time ranges into a local incident report.
Log Line Cleaner

Clean noisy logs by removing timestamps, ANSI colors, blank lines, long lines, or non-error entries in your browser.
Logarithm Calculator

log_b(x), ln, log₁₀, log₂ and antilog in one place — change-of-base steps shown, one-click copy, browser-only
Logrotate Cheatsheet

Logrotate cheat sheet — directives, CLI flags, postrotate scripts, pitfalls, and copy-ready config templates for nginx, rsyslog, and app logs.
Loki Cheatsheet

Grafana Loki cheat sheet — 80+ entries covering LogQL stream selectors, line filters, parsers, metric queries, aggregations, Promtail stages, Loki config, and HTTP API.
Lorem Ipsum Generator

Classic Lorem Ipsum filler text — paragraphs, sentences, or words — copy in one click, browser-only
Low Pass Filter Cutoff Calculator

RC and LC filter −3 dB cutoff frequency · fc = 1/(2πRC) · reverse-solve the capacitor or resistor · browser-only
Luhn Validator

Check any number against the Luhn (mod 10) algorithm, see the doubling math step by step, or compute the missing check digit, all in your browser
MAC Address Deduplicator

Find duplicates and keep one clean copy of mac addresses from pasted text or uploaded local files.
MAC Address Extractor

Extract, dedupe, and export mac addresses from pasted text or uploaded local files.
MAC Address Generator

Random MAC addresses in colon, hyphen, Cisco dotted or bare hex, with locally-administered and unicast bits and optional vendor OUI, all in your browser
MAC Address List Converter

Convert mac addresses from pasted text or uploaded local files.
MAC Address List Validator

Validate and explain issues in mac addresses from pasted text or uploaded local files.
MAC Address Normalizer

Normalize, sort, and prepare mac addresses from pasted text or uploaded local files.
Mailto Link Generator

Build a mailto link with recipients, cc, bcc, subject and a multi-line body. Correct URL encoding, copy as plain URL or HTML anchor, all in your browser.
Markdown Cheat Sheet

Markdown syntax cheat sheet — every rule with live preview side by side, GFM + flavors.
Markdown Editor with Live Preview

Markdown editor with live split-pane preview — GFM tables, fenced code with syntax highlight, math, emoji, table of contents, export as HTML / PDF-ready.
Markdown Link Extractor

Upload Markdown and extract inline links, reference links, images, and bare URLs into a local CSV.
Markdown Table Generator

Build Markdown tables visually — add/remove rows, column alignment, paste from Excel / CSV — browser-only
Markdown Table to CSV

Paste a Markdown pipe table, get RFC 4180 CSV: escaped pipes, quoted commas, comma / semicolon / tab delimiters, all in your browser
Markdown to AsciiDoc Converter

Turn GitHub Markdown into clean AsciiDoc, headings, source blocks, url[text] links and image:: macros, all in your browser
Markdown to BBCode Converter

Paste Markdown, get forum BBCode in real time. Bold, links, lists, code blocks and quotes mapped to [b] [url=] [list] [code] [quote], browser only
Markdown to Confluence Converter

Paste Markdown, get Confluence wiki markup — h1. headings, {code} panels, ||tables|| and {quote} blocks, all in your browser
Markdown to HTML

Convert Markdown to clean HTML — headings, lists, code, links, images, tables — instant live preview, browser-only
Markdown to Jira

Paste GitHub-flavored Markdown, get Jira wiki markup back — headings, bold, code blocks, tables, links, all in your browser
Markdown to JSX

Turn Markdown into React-ready JSX — one paste from README to a real component, with class becoming className and code blocks intact. Browser-only.
Markdown to Org-mode

Convert Markdown to Emacs Org-mode with star headlines, /italic/ slashes, ~code~ verbatim and [[url][text]] links, all in the browser
Markdown to Plain Text

Strip Markdown to clean plain text — headings, bold, links, code, lists, tables, HTML all flattened — browser-only
Markdown to reStructuredText

Convert Markdown to RST for Sphinx and Python docs, with matched heading underlines, double-backtick code and `text <url>`_ links, in the browser
Markdown to Slack

Paste standard Markdown, get Slack mrkdwn back: single-star bold, underscore italic, single-tilde strike, angle-bracket links, all in your browser
Markdown to Textile

Paste GitHub-flavored Markdown, get Textile markup back for Redmine and wikis, with headings, bold, code blocks, links and images converted in your browser
Markdown TOC Generator

Markdown TOC generator — paste your markdown, get a clean table of contents with anchor links.
MD5 / SHA Hash Generator

Compute MD5 / SHA-1 / SHA-256 / SHA-384 / SHA-512 hashes, all five at once, browser-only
Meeting Cost Calculator

Meeting cost calculator — see how much that meeting is costing in real-time, with team salary data and overhead multiplier.
Meta Tag Generator

Generate SEO meta tags — title, description, Open Graph, Twitter Card, Schema.org.
MIDI Note Number Converter

MIDI number ⇄ note name ⇄ frequency — note 60 is middle C, A4 = 440 Hz, cents off, C3/C4 toggle — browser-only
MIME Type Lookup

File extension ⇄ MIME type lookup — 130+ types, both directions, copy the exact Content-Type — browser-only
Mock Data Generator

Generate realistic mock JSON / CSV / SQL data — names, emails, dates, addresses, nested objects.
Modular Exponentiation Calculator

Compute a^b mod m with fast exponentiation and BigInt, plus modular inverse and step-by-step squaring, all in your browser
Modulo Calculator

a mod n in both conventions — the % your language returns AND the math mod that is never negative, plus floor quotient, modular power and inverse
MongoDB Cheatsheet

MongoDB cheat sheet — 80+ shell commands & query operators for CRUD, aggregation, indexing, replication.
MongoDB ObjectId Generator & Decoder

Generate ObjectIds, decode the embedded timestamp, build $gte/$lte bounds for a time range — all in your browser
Morse Code Translator

Text to Morse code and back — encode, decode, audio playback, ITU standard.
Multicultural Name Generator

Random names from 11 cultures — Chinese, English, Japanese, Korean, Arabic, Russian + 5 European.
NanoID Generator

Generate URL-safe NanoIDs with a custom alphabet, adjustable length, and a live collision-probability readout — entirely in your browser.
Netlify Redirects Cheatsheet

Netlify _redirects and netlify.toml cheatsheet for rewrites, proxies, SPA fallbacks, splats, status codes, and country/language rules.
Neumorphism Generator

Neumorphism CSS generator — soft-UI inset/outset shadow pair, live light-source direction, 12 presets, copy CSS/Tailwind/SwiftUI.
Next.js Cheatsheet

Next.js 15 cheat sheet — App Router, Server Components, Server Actions, dynamic routes, with examples and pitfalls.
Nginx Cheatsheet

Nginx cheat sheet — common configs, location/server blocks, SSL, reverse proxy, gzip, real examples & gotchas.
nginx Docker Config Generator

Generate nginx.conf and Docker CMD for container log routing — access_log /dev/stdout, error_log /dev/stderr, daemon off.
npm / yarn / pnpm Cheatsheet

npm / yarn / pnpm cheat sheet — 80+ commands across init, install, scripts, publish, with cross-tool comparison.
Number Extractor

Pull every number out of any text: integers, decimals, negatives, 1,234 commas, percents and 6.02e23, with instant sum and average
Number Formatter

One number in, every format out: thousands grouping, currency, percent, scientific, engineering, compact (K/M/万), ordinal, byte size — plus reverse parsing. 100% browser-only.
Number Sequence Generator

Generate a list of numbers from start to end by step or count, with zero-padding, prefix, suffix and any separator, all in your browser
OAuth Scope Cheatsheet

OAuth 2.0 scope reference — 60+ scopes across Google, GitHub, Microsoft, Slack, Spotify, Discord and more, with access level, use cases and risk rating.
Ohm's Law Calculator

Enter any two of voltage, current, resistance, or power — get the other two plus the formula used — with mV/V/kV, µA/mA/A, Ω/kΩ/MΩ, mW/W/kW prefixes — browser-only.
OKLCH Color Converter

OKLCH ⇄ HEX, RGB and HSL with a full sRGB → OKLab → OKLCH pipeline, live swatch and sRGB gamut warning — browser-only
Op-Amp Gain Calculator

Inverting −Rf/Rin and non-inverting 1+Rf/Rin gain, in V/V and dB, with output voltage and a reverse resistor solver, browser-only
Open Graph & Social Card Preview

See your og:title, og:image and twitter:card exactly as Google, X, Facebook, LinkedIn, Slack and Discord will render them — before you ship.
OpenAPI Endpoint Auditor

Audit OpenAPI JSON or YAML for endpoint coverage, missing operation IDs, security gaps, and weak response documentation.
ORCID Validator

Check an ORCID iD check digit with ISO 7064 MOD 11-2, complete the check digit from the first 15 digits, validate a whole list, all in your browser
otpauth URI Generator

Build an otpauth:// 2FA setup URI from issuer, account and Base32 secret, parse one back, then turn it into a QR code, browser-only
package.json Cheatsheet

package.json field reference — 55+ fields explained with real examples, bilingual, searchable.
Package Lock Dependency Auditor

Inspect package-lock.json, pnpm-lock.yaml, or yarn.lock for duplicate versions, risky sources, prereleases, and missing integrity.
Palindrome Checker

Tells you if text reads the same backwards, finds the longest palindrome inside, handles Chinese and emoji, runs in your browser
Parallel & Series Resistor Calculator

Add resistors in series, combine them in parallel, and reverse-engineer a target value from two standard parts, all in the browser
Password Entropy Calculator

Entropy in bits, full character pool, and brute-force crack time across four attacker speeds, computed locally in your browser
Password Generator

Generate strong, cryptographically random passwords and passphrases — entirely in your browser.
Password Leak Checker

Password leak checker — check if your password has been seen in known breaches using k-anonymity (HIBP API style), the password never leaves your browser.
Password Strength Checker

Check password strength — entropy, time-to-crack, breach pattern check (offline).
PDF Merger

PDF merger — combine multiple PDFs into one, drag to reorder pages, 100% client-side with pdf-lib.
PDF Metadata Extractor

Upload PDFs and extract document metadata, page-count hints, encryption flags, and producer details locally.
PDF Splitter

PDF splitter — extract pages or split by range, every page becomes a PDF, 100% client-side with pdf-lib.
Placeholder Image Generator

Generate placeholder images instantly — size, color, text, PNG/JPG/WebP.
Playfair Cipher Encoder & Decoder

Encrypt and decrypt with a 5x5 keyword square, digraph pairs and a live grid, browser-only
Pluralizer

Turn singular English nouns into plurals and back, with irregulars, -ies, -ves and uncountables handled, all in your browser
pnpm Workspace Cheatsheet

Dense, searchable pnpm workspace reference — 60+ commands covering filter syntax, workspace protocols, recursive scripts, and monorepo pitfalls.
Polar / Rectangular Coordinate Converter

Convert (x, y) to (r, θ) and back, degrees or radians, with a live coordinate diagram, browser-only
Polybius Square Cipher Encoder & Decoder

Turn letters into 5x5 grid coordinates and back, with a keyword square, origin switch and a live grid, browser-only
Pomodoro Timer

Pomodoro timer — 25/5 classic, plus 50/10 and 90/15 long-focus modes, with sound, browser tab title, daily stats.
PostgreSQL Cheatsheet

PostgreSQL cheat sheet — 80+ commands & functions for psql, JSONB, CTEs, window functions, indexing, partitioning, advanced extensions.
Power-to-Weight Ratio Calculator

Power ÷ weight in W/kg, hp/ton and kW/kg — cars and cycling, forward and reverse, browser-only
PPI Calculator

Pixel density, dot pitch, physical size, aspect ratio & a retina check from resolution + diagonal — all in your browser
Prime Factorization Calculator

Break any integer into prime factors with exponent form, divisor count and full divisor list, exact BigInt math, browser-only
Prime Number Calculator

Test primality · factorize · list primes in a range · find the N-th prime — exact BigInt math, browser-only
Prometheus Cheatsheet

Prometheus cheat sheet — 90+ entries covering PromQL selectors, aggregations, functions, alerting rules, recording rules, HTTP API, and relabeling.
Prompt Template Library

200+ prompt templates for ChatGPT, Claude, Gemini — copy-paste, browse by use case.
Properties ⇄ JSON Converter

Java/Spring .properties to JSON and back, with dotted-key nesting, line continuations and full escape handling, all in your browser
Punycode / IDN Converter

Unicode ⇄ Punycode for internationalized domains — münchen.de ⇄ xn--mnchen-3ya.de — per-label, email-aware, browser-only
PWM Duty Cycle Calculator

Frequency + duty cycle to period, on-time, off-time and average voltage — reverse-solve duty from a measured pulse width — browser-only
PX REM EM Converter

CSS px ↔ rem ↔ em converter — visual scale, base font size adjustable.
Python Cheatsheet

Python cheat sheet — 100+ idiomatic Python snippets for string, list, dict, file, async, with real examples.
QR Code Decoder

QR code decoder — drag a QR image or paste URL, see the text/URL inside, plus phishing & risky-link warnings.
Batch QR Code Decoder

Drop a folder of QR images and get every decoded URL in one table — fast batch audit for packaging, posters, and print runs.
QR Code Generator

Generate QR codes from text, URL, WiFi or vCard — customize color and size, download as PNG or SVG.
Query String to JSON Converter

Parse a URL query string into JSON and rebuild a query string from JSON — two-way, live, with array + nested object conventions — 100% in your browser
Quoted-Printable Encoder / Decoder

Quoted-Printable encode and decode by UTF-8 bytes, the way email MIME does it, with =XX escapes, trailing-space handling and 76-column soft wraps, all in your browser
RabbitMQ Cheatsheet

RabbitMQ cheat sheet — 90+ commands and patterns for queues, exchanges, clustering, and common pitfalls.
Rail Fence Cipher Encoder & Decoder

Encrypt, decrypt and brute-force a rail fence zigzag cipher, with a live grid, rail count plus offset, browser-only
RC Time Constant Calculator

τ = R · C — charge and discharge curve, 1τ (63%) and 5τ (99%) markers, Ω/µF auto units — browser-only
React Hooks Cheatsheet

React hooks cheat sheet — all 17 built-in hooks (useState / useEffect / useMemo / useTransition / useFormStatus...) with real examples and pitfalls.
Redis Cheatsheet

Redis cheat sheet — 80+ commands across strings, hashes, lists, sets, sorted sets, pub/sub, streams, scripts, with examples and pitfalls.
Regex Builder from Examples

Regex from examples — paste positive matches + negative non-matches, get a regex that hits all positives and rejects all negatives, with multiple candidate patterns ranked by specificity.
Regex Cheatsheet

Interactive regex cheat sheet — quick reference for every flavor (JS, Python, PCRE).
Regex Escape

Turn literal text into a safe regex pattern: a.b becomes a\.b, copy the ready /…/ form, reverse it too, all in your browser
Regex Match Extractor

Pull every regex match out of any text, grab a single capture group, dedupe, one per line, copy in one click, all in the browser
Regex Tester

Test JavaScript regex live — match highlighting, group capture, replace preview, flag toggles — browser-only
Regex Visualizer

Regex visualizer — see your pattern as a railroad diagram + matching state machine, with capture groups highlighted.
Remove Accents

Strip diacritics from Latin text, café to cafe, ñ to n, ß to ss, runs entirely in your browser
Remove Line Breaks

Strip or replace line breaks, join wrapped lines into running text — keep-paragraphs mode, CRLF/CR/LF normalize, live preview — browser-only
Resistor Color Code Calculator

Decode 4, 5 and 6-band resistors to Ω, tolerance and tempco — or go the other way, with a live color-band drawing
Resume Template Builder

Resume template builder — fill a form, get a clean PDF resume in 3 templates (modern / classic / minimal), bilingual.
Reverse Text Generator

Reverse text by character, word or line, flip each word, or turn writing upside down — Unicode and emoji safe, runs in your browser
Robots.txt Auditor

Check robots.txt for user-agent groups, allow and disallow rules, sitemap declarations, crawl-delay, and unsupported directives.
robots.txt Generator

Generate robots.txt with templates for common crawlers (Google, Bing, AI scrapers).
Rocket Equation Delta-v Calculator

Tsiolkovsky Δv = ve·ln(m0/mf) — solve from exhaust velocity or specific impulse, reverse-solve propellant, mass ratio, browser-only
ROT13 Encoder & Decoder

ROT13 / ROT47 / Caesar cipher — encode and decode in your browser, instant.
ROT47 Encoder & Decoder

Rotate all visible ASCII by 47. Digits and symbols change too, fully self-inverse, runs in your browser.
Routing Number Validator

Check a 9-digit ABA routing number with the public 3-7-1 checksum, read its Federal Reserve routing symbol, one-click copy, browser-only
Rust Cheatsheet

Rust cheat sheet — 100+ snippets covering ownership, borrowing, lifetimes, traits, async, error handling.
Scientific Calculator

Scientific calculator — sin / cos / log / sqrt / power, with full keyboard input + history, deg/rad mode.
Scientific Notation Converter

Plain ⇄ scientific (a×10ⁿ) ⇄ engineering ⇄ E-notation — with significant figures, exact big/small numbers — browser-only
Scytale Cipher Encoder & Decoder

Encrypt and decrypt the ancient Spartan scytale rod cipher, with a live rod grid and an adjustable diameter, browser-only
Semantic Version Deduplicator

Find duplicates and keep one clean copy of semantic versions from pasted text or uploaded local files.
Semantic Version Extractor

Extract, dedupe, and export semantic versions from pasted text or uploaded local files.
Semantic Version List Converter

Convert semantic versions from pasted text or uploaded local files.
Semantic Version List Validator

Validate and explain issues in semantic versions from pasted text or uploaded local files.
Semantic Version Normalizer

Normalize, sort, and prepare semantic versions from pasted text or uploaded local files.
Semver Compare

Tell which semantic version is newer, sort a whole list, and check ^ ~ >= ranges, all in the browser
Semver Increment

Bump a version the npm way and see major, minor, patch and every pre-release result at once, all in the browser
Shell Escape

Quote any string for bash safely: single-quote wrap, double-quote escape, backslash mode, and reverse, all in your browser
Sitemap URL Auditor

Paste sitemap XML and audit URL count, HTTP links, duplicates, trailing-slash conflicts, query parameters, lastmod freshness, and extensions.
URL Slug Generator

Turn any title into a clean URL slug — lowercase, dashes, ASCII-safe transliteration, multiline batch — browser-only
Snowflake ID Decoder

Decode a 64-bit Snowflake into timestamp, machine id and sequence, with Twitter, Discord and custom epochs, all in BigInt, browser-only
SQL Cheatsheet

SQL cheat sheet — 100+ statements covering SELECT, JOIN, window functions, indexing, MySQL/PostgreSQL/SQLite differences.
SQL Formatter

Format and beautify SQL — supports MySQL, PostgreSQL, BigQuery, SQLite and 17 more dialects.
SQL Minifier

Strip comments and whitespace from SQL — collapse to one compact line, string literals stay untouched, runs entirely in your browser.
SSH Config Cheatsheet

SSH config cheatsheet — 50+ directives for ~/.ssh/config with copy-ready examples and common pitfalls.
Stepper Motor Steps Calculator

Step angle + microstepping + transmission → steps/rev, steps/mm, steps for any travel — Marlin/Klipper config, browser-only
Story Points to Time Converter

Team velocity + sprint length + team size → what 13 story points actually means in hours, days and sprints — both directions, browser-only.
String Escape Converter

Paste once — see escaped strings for JSON, Python, Go, C#, Rust, Java, C, Ruby, PHP, Swift, Kotlin & JS side by side
String Escape / Unescape

Escape & unescape strings for JSON, JS, Java, C, SQL, Shell, HTML, CSV & regex — both directions — browser-only
String Similarity Checker

Levenshtein edit distance, Dice, Jaro-Winkler and LCS side by side, with a 0-100% match score, all in your browser
Strip HTML Tags

Paste HTML source, get clean plain text. Block tags become line breaks, entities decode, allow-list keeps chosen tags, script content gets removed — all in your browser.
Svelte Cheatsheet

Svelte 5 cheat sheet — runes ($state, $derived, $effect), snippets, props, stores, with Svelte 4 comparison.
SVG Asset Auditor

Audit SVG viewBox, dimensions, scripts, external references, styles, ids, classes, title, and desc tags.
SVG Blob Generator

Generate smooth organic blob shapes — adjustable complexity, randomness, seed — export SVG / CSS clip-path — 100% browser-only
SVG Optimizer

SVG optimizer — strip comments/metadata/empty attributes, round path decimals, collapse useless groups, minify in browser. No upload.
SVG to Data URI / CSS Background

Inline any SVG as a data URI — URL-encoded (smaller) or base64 — with ready-to-paste CSS, HTML and bare-URI output, side-by-side size diff, 100% in-browser.
SVG to JSX

Paste SVG, get a React component — attributes camelCase, style becomes an object, wrap with {...props} passthrough. Browser-only.
SVG to PNG Converter

Rasterize SVG to PNG in your browser — custom size, 1×/2×/3× HiDPI scale, true transparent background, never uploaded.
System Prompt Builder

Turn role, task, constraints, and output rules into a structured system prompt you can copy.
Tabs to Spaces Converter

Convert tabs to spaces and spaces to tabs, real tab-stop alignment, leading-indent or whole-line, all in your browser
Tailwind CSS Cheatsheet

Tailwind CSS cheat sheet — 100+ utility classes (spacing, color, flex, grid, typography, responsive) with live preview.
Tap Code Translator

Knock cipher on a 5×5 grid, C and K share a cell, row taps then column taps, decode back to text, all in your browser
Terraform Cheatsheet

Terraform cheat sheet — 90+ commands for init, plan, apply, state, workspaces, import, and debug with real examples.
Text Box Drawing Generator

Wrap text in single, double, rounded, bold, ascii or stars boxes with CJK-aware alignment, padding and a title row, all in your browser
Text Deduplicator

Remove duplicate lines from any list — case-sensitive optional, whitespace-trim optional, count duplicates — browser-only
Text Diff

Compare two blocks of text — line-by-line additions, deletions, equal — colour highlighted, browser-only
Text File Cleaner

Upload a text file and remove BOM, null bytes, trailing spaces, and excessive final blank lines locally.
Text File Line Ending Converter

Upload or paste text and convert CRLF, CR, and LF endings to a consistent LF or CRLF output locally.
Text Repeater

Repeat any text N times with newline, space, comma or custom separators, optional numbering and a wrap, browser-only
Text Sorter

Sort lines alphabetically, naturally (file2 < file10), numerically, by length — locale-aware — browser-only
Text to Binary Converter

Text to binary (and back) — UTF-8 aware, 8/16/32 bit grouping, emoji safe.
Text to Hex Converter

Text ⇄ hexadecimal by UTF-8 bytes — Chinese and emoji safe, picks your separator and case, decodes messy pasted hex — runs in your browser
Text Wrap

Hard-wrap text at any column width, by word or by character, with optional line prefix, all in your browser
Three-Phase Power Calculator

P = √3 · VL · IL · cosφ — active kW, apparent kVA, reactive kVAR and reverse line current — browser-only
Unix Timestamp Converter

Unix timestamp ⇄ human date — seconds / milliseconds / ISO 8601 — UTC and local — browser-only
Timezone Meeting Planner

Plan meetings across timezones — see when everyone's working hours overlap.
TOML Formatter + Converter

TOML formatter + converter — format/validate TOML 1.0, convert TOML ↔ JSON ↔ YAML, with error line/column.
TOML to JSON Converter

Paste TOML, get clean JSON instantly — full TOML 1.0 support, error messages with line numbers, 100% in-browser
TOTP Generator

Base32 secret in, live 6-digit code out, 30s countdown and next code, SHA1/256/512, 100% in-browser, RFC 6238
Traditional ⇄ Simplified Chinese Converter

Traditional ⇄ Simplified Chinese — fast, character-level, no API.
Transformer Turns Ratio Calculator

Np/Ns = Vp/Vs = Is/Ip — turns ratio, secondary voltage, current and impedance transform, step-up vs step-down — browser-only
TSV to CSV Converter

Turn tab-separated files into standards-friendly CSV with proper quoting, download, and local processing.
TSV to JSON Converter

Tab-separated data to JSON, header detection, type inference, quoted tab/newline fields, browser-only
Twitter Card Generator

Build twitter:card meta tags for X with a live card preview, Open Graph fallback and one-click copy, all in your browser
Two's Complement Converter

Signed decimal to two's complement binary and hex at 4, 8, 16, 32, 64 bits, with sign-magnitude and one's-complement steps, runs in your browser
TypeScript Cheatsheet

TypeScript cheat sheet — 100+ snippets for types, generics, utility types, narrowing, async patterns.
TypeScript Config Cheatsheet

TypeScript tsconfig.json cheat sheet — 55+ options with defaults, examples, and gotchas.
TypeScript to Zod Schema

TypeScript to Zod schema converter — paste interface/type, get z.object() schema, supports unions/optionals/nested/generics/enum/Record/Map/Set.
Typing Speed Test

Typing speed test — WPM, accuracy, real-time mistakes, English + Chinese pinyin modes.
ULID Decoder

Pull the timestamp and randomness back out of a ULID — decode one or paste many, with UTC, ISO and local time — 100% in your browser
ULID Generator

Sortable, URL-safe unique IDs — batch generate, monotonic mode, decode the timestamp back out — 100% in your browser
Unicode Character Inspector

Inspect any text character-by-character: code points, UTF-8/UTF-16 bytes, HTML entities, JS escapes, names, and hidden zero-width / confusable glyphs.
Unicode Code Point Explorer

Inspect any character — code point, UTF-8 bytes, UTF-16 encoding, Unicode category, script, and block — instant, browser-only
Unicode Code Point Inspector

Paste text → get a per-code-point table: U+XXXX, UTF-8 bytes, UTF-16, HTML entity, JS escape, character name.
Unicode Escape Converter

Text ⇄ Unicode escapes — \uXXXX, \u{1F600}, 😀, CSS \1F600 — emoji + CJK done right, browser-only
Unicode Inspector and Normalizer

Inspect code points, names, categories, UTF-8 bytes and normalize text to NFC, NFD, NFKC or NFKD entirely in your browser.
Unicode Normalizer

Normalize text to NFC, NFD, NFKC or NFKD, see code-point and byte counts shift, spot which characters changed, copy in one click, all in your browser
Unslugify

Turn my-blog-post, user_first_name and parseHTMLContent back into readable text, browser-only
URL Deduplicator

Find duplicates and keep one clean copy of urls from pasted text or uploaded local files.
URL Encoder Decoder with Query Parameter Table

Encode, decode, inspect query parameters, process bulk URL lists, and copy clean outputs entirely in your browser.
URL Encoder / Decoder

Encode and decode URL-unsafe characters — query strings, path segments, full URLs — instant, browser-only
URL Extractor

Extract, dedupe, and export urls from pasted text or uploaded local files.
URL List Converter

Convert urls from pasted text or uploaded local files.
URL List Validator

Validate and explain issues in urls from pasted text or uploaded local files.
URL Normalizer

Normalize, sort, and prepare urls from pasted text or uploaded local files.
URL Parser

Break any URL into protocol, host, port, path, query and hash, with a decoded parameter table, all in your browser
URL Query Params Extractor

Extract, deduplicate, inspect, copy, and export query parameters from one URL or many URLs locally.
URL Query String Parser & Builder

Paste a URL, see every parameter decoded in a table; edit the rows and get a clean, correctly-encoded query string back — %20 or +, sorted or not, in your browser
User-Agent Parser

Parse any User-Agent string into browser, engine, OS, device type and bot flag — paste a log line or read your own — browser-only
UTF-8 Byte Counter

Count UTF-8 bytes, UTF-16 code units, Unicode code points and characters in any string, right in your browser
UTM Link Builder

UTM link builder — track campaign source, medium, name. GA4/Google Analytics compatible.
UUID Deduplicator

Find duplicates and keep one clean copy of uuids from pasted text or uploaded local files.
UUID Extractor

Extract, dedupe, and export uuids from pasted text or uploaded local files.
UUID Generator

Generate v4 random, v7 time-ordered, NIL, and Short UUIDs instantly — entirely in your browser.
UUID Inspector

Paste a UUID, read back its version, variant and the timestamp baked into the bytes
UUID List Converter

Convert uuids from pasted text or uploaded local files.
UUID List Validator

Validate and explain issues in uuids from pasted text or uploaded local files.
UUID Normalizer

Normalize, sort, and prepare uuids from pasted text or uploaded local files.
UUIDv5 Generator

Namespace UUID from a name via SHA-1 — deterministic, RFC 4122, browser-only
UUIDv7 Generator

Time-ordered, sortable UUIDs by RFC 9562: batch generate, monotonic mode, decode the embedded timestamp, all in your browser
Vector Calculator

Add, subtract, scale, dot, cross, magnitude, angle, unit vector and projection for 2D and 3D vectors — browser-only
Video Bitrate Calculator

File size = bitrate × duration ÷ 8 — solve any one of bitrate, length or size, add audio, copy in one click — browser-only
Vigenère Cipher Encoder / Decoder

Encrypt and decrypt with a keyword, polyalphabetic shift, case kept, non-letters passed through, browser-only
Vim Cheatsheet

Vim cheat sheet — 100+ commands covering modes, motions, edits, search, registers, splits, with mnemonics.
Vite Config Cheatsheet

Vite config cheat sheet — 60+ vite.config.ts options with defaults, examples, and pitfalls.
Voltage Divider Calculator

Vout = Vin · R2 / (R1 + R2), reverse-solve any resistor, see current, power and how a load drags the output down. Browser-only.
Voltage Drop Calculator

Wire and cable voltage drop from current, run length, conductor size and material, with the 3% limit check, copper vs aluminium, single-phase and three-phase, browser-only
Vue 3 Cheatsheet

Vue 3 cheat sheet — Composition API, reactivity, components, directives, Pinia, with side-by-side Options API comparison.
WCAG Color Contrast Fixer

WCAG color contrast fixer — input fg/bg, get current ratio, auto-suggest 4 fixed colors hitting AA/AAA while preserving hue.
Week Number Calculator

What week number is today? ISO 8601 (Mon-start) + US (Sun-start), plus year + week → date range — browser-only
Whitespace Visualizer

See every space, tab, newline and hidden character — middle-dot spaces, arrow tabs, pilcrow line breaks, trailing-space highlight, browser-only
WiFi QR Code Generator

Turn your WiFi name + password into a scan-to-connect QR code — WPA/WPA2/WPA3, WEP or open, hidden networks, PNG/SVG export. Password never leaves the tab.
Wire Gauge Calculator (AWG)

AWG to mm, area, ampacity and resistance, both ways, with a full 4/0 to 40 reference chart, browser-only
Wye-Delta Resistor Calculator

Convert a three-terminal resistor network between wye (Y / T) and delta (Δ / π) — Δ→Y and Y→Δ both directions, exact formulas, one-click copy — browser-only
XML Formatter & Validator

Pretty-print, minify, and validate XML in your browser — preserves CDATA, comments, and namespaces.
XML to CSV Converter

Turn repeating XML records into a CSV table, columns are the union of every field, attributes optional, custom delimiter, RFC 4180 escaping, browser-only
XML ⇄ JSON Converter

XML to JSON converter — preserves attributes, nested elements, CDATA. Reversible.
XML to YAML Converter

Paste XML, get clean YAML. Attributes as @ keys, repeated tags as lists, mixed text kept, valid YAML 1.2. Browser only.
YAML Formatter & Validator

Format and beautify YAML — re-indent, validate, minify, sort keys.
YAML to CSV Converter

Turn a YAML list of objects into an RFC 4180 CSV — column union, JSON or flattened nested values, comma / semicolon / tab, browser-only
YAML ⇄ JSON Converter

Convert between YAML and JSON — both directions, pretty-printed, error messages with line numbers — browser-only
YAML to XML Converter

Turn YAML into clean, indented XML. Keys become elements, lists repeat, @keys become attributes, every value escaped. Browser-only.
Zero Width Character Detector

Find and strip zero-width spaces, the BOM, no-break spaces and other invisible characters, then copy clean text — runs in your browser
ZIP Manifest Inspector

Read a ZIP central directory locally and flag traversal paths, encryption, duplicate names, and risky ratios.

555 Timer Calculator

Add Line Numbers

AES Text Encryptor

Affine Cipher Encoder & Decoder

Age Difference Calculator

AI Eval Planner

AI Model Comparison

AI Token Counter

Angle Converter

Antenna Length Calculator

Apache Cheatsheet

API Key Generator

API Rate Limit Cheatsheet

App Store Keywords Checklist

Armstrong Number Checker

ASCII Art Generator

ASCII Table Generator

ASCII Table Reference

Aspect Ratio Calculator

Atbash Cipher

Avatar Generator

awk + sed Cheatsheet

AWS CLI Cheatsheet

AWS IAM Cheatsheet

AWS S3 Cheatsheet

Backup Codes Generator

Bacon Cipher Encoder & Decoder

Barcode Generator

Number Base Converter

Base32 / Base58 Encoder & Decoder

Base62 Encoder & Decoder

Base64 Block Deduplicator

Base64 Block Extractor

Base64 Block List Converter

Base64 Block List Validator

Base64 Block Normalizer

Base64 Encoder & Decoder

Base64 Image Converter

Base64 Image Data URI Converter

Base64 to File Converter

Base64 to Hex Converter

Base64URL Encoder Decoder for JWT-Safe Strings

Base85 / Ascii85 Encoder & Decoder

Bash Cheatsheet

Basic Auth Header Generator

Batch File Rename Planner

Battery Life Calculator

BBCode to HTML Converter

BCD Converter

Bcrypt Generator

Beaufort Cipher

BEM Class Name Generator

Binary Calculator

Bit Shift Calculator

Bitwise Calculator

CSS Border Radius Generator

CSS Box Shadow Generator

CSS Design Token Contrast Matrix

JWT Decoder and Claims Inspector

Business Days Calculator

Cache-Control Builder

Caesar Cipher Encoder & Decoder

Capacitor Code Calculator

Capacitor Energy Calculator

Case Converter

Character Frequency Counter

Chinese Pinyin Converter

CSS Clip-Path Generator

Cloudflare DNS Cheatsheet

Code Screenshot Generator

Collatz Conjecture Calculator

Color Blindness Simulator

Color Contrast Checker

Color Converter

Color Shades Generator

Column Align

Columnar Transposition Cipher

Common Ports Reference

Continued Fraction Calculator

Conventional Commit Generator