Does this upload my YAML / JSON?

No. Parsing uses the standard `yaml` JS library (eemeli/yaml) running in your browser. Nothing leaves the tab.

YAML 1.2 (the modern spec). Supports anchors, tags, flow & block style, multiline scalars. Does NOT support YAML 1.1 quirks like `yes`/`no` as booleans (per the 1.2 spec, `yes` is a string).

Can I round-trip without losing data?

Numbers, strings, booleans, nulls, arrays, objects round-trip cleanly. YAML-specific features (anchors that share refs, custom tags) flatten to plain JSON shapes. Comments are dropped (JSON has no comments).

What does the indent option do?

Controls how many spaces to use per nesting level in the output. 2 (default) is the most common; 4 is also popular. Tabs are not supported (intentional — YAML spec forbids tab indentation).

Why does my JSON key order change after converting to YAML and back?

Both `yaml` and `JSON.stringify` preserve insertion order, so a clean round-trip keeps keys in place. Order only shifts if you feed JSON with duplicate keys (the last one wins, per spec) or if your YAML uses a merge key (`<<:`) that pulls in an anchor — the merged keys land where the anchor resolves. Example, `{"b":1,"a":2}` stays `b` then `a`; it is not sorted alphabetically.

Pasting a Kubernetes manifest into a JSON-only API client

Your deployment lives as a 120-line YAML manifest, but the admission webhook you are testing only accepts JSON. Paste the YAML here, copy the JSON out, and fire it at the endpoint in Postman. The line-numbered error catches the stray tab on line 47 before kubectl ever sees it.

Reading a dense JSON config that a teammate sent

Someone drops a 200-key minified JSON blob in the channel and asks "is the timeout right?" Paste it, flip to YAML, and the nesting plus comments-free layout reads like prose. You spot `timeoutMs: 3000` three levels down in five seconds instead of squinting at one line.

Converting a docker-compose snippet for a Node script

You are scripting a migration and need the service block from docker-compose.yml as a plain JS object. Paste the YAML, get JSON, drop it straight into your `.ts` file as a literal. Anchors and the `<<:` merge keys flatten out, so the object is already resolved.

Sanity-checking GitHub Actions YAML indentation

A workflow keeps failing with "did not find expected key". Paste the .github/workflows/ci.yml here; if it is valid YAML you get JSON back instantly, if not you get the exact line. Two spaces vs four under `jobs:` is the usual culprit, and the error points right at it.

YAML ⇄ JSON Converter — Both Directions, with Line-numbered Errors

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

Runs locally
Category Format Converter
Best for Turning pasted content or local files into a handoff-friendly format.

DirectionIndent (spaces)

Input

Output

What this tool does

Free online YAML ⇄ JSON converter. Paste YAML and get JSON, or paste JSON and get YAML — both directions instant. Pretty-printed output with configurable indent. Surfaces parser errors with line numbers so you can fix invalid YAML in place. 100% client-side, your config never leaves the browser.

Tool details

Input: Text + Numbers + Structured content; The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output: Live result + Copy; The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy: Browser-side processing; The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share: No account required; Open the page and use it; whether results survive refresh depends on the tool.
Performance budget: Initial JS <= 30 KB; No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit: Format Converter · Developer; Category and role tags drive related tools, internal links, and quick fit checks.

How to use

1. Input

Paste or drop your content into the tool panel.
2. Process

Click the button. All processing is local in your browser.
3. Copy / Download

Copy the result or download to disk in one click.

How YAML ⇄ JSON Converter fits into your work

Use it when the main problem is getting content from one practical format into another.

Conversion jobs

Turning pasted content or local files into a handoff-friendly format.
Previewing a conversion before you use it in a larger workflow.
Cleaning small format mismatches without opening a full editor.

Conversion checks

Try a small sample first when the source format is messy.
Check character encoding, separators, and line endings after conversion.
Keep the source until the converted output has been reviewed.

Good next steps

These links move the current task into a more complete workflow.

Real-world use cases

Pasting a Kubernetes manifest into a JSON-only API client
Your deployment lives as a 120-line YAML manifest, but the admission webhook you are testing only accepts JSON. Paste the YAML here, copy the JSON out, and fire it at the endpoint in Postman. The line-numbered error catches the stray tab on line 47 before kubectl ever sees it.
Reading a dense JSON config that a teammate sent
Someone drops a 200-key minified JSON blob in the channel and asks "is the timeout right?" Paste it, flip to YAML, and the nesting plus comments-free layout reads like prose. You spot `timeoutMs: 3000` three levels down in five seconds instead of squinting at one line.
Converting a docker-compose snippet for a Node script
You are scripting a migration and need the service block from docker-compose.yml as a plain JS object. Paste the YAML, get JSON, drop it straight into your `.ts` file as a literal. Anchors and the `<<:` merge keys flatten out, so the object is already resolved.
Sanity-checking GitHub Actions YAML indentation
A workflow keeps failing with "did not find expected key". Paste the .github/workflows/ci.yml here; if it is valid YAML you get JSON back instantly, if not you get the exact line. Two spaces vs four under `jobs:` is the usual culprit, and the error points right at it.

Common pitfalls

Indenting YAML with tabs. The parser rejects them per spec, so a config copied from an editor that auto-inserts tabs fails on line 1. Convert tabs to spaces first, or set your editor to soft tabs.
Expecting `yes`, `no`, `on`, `off` to become booleans. Under YAML 1.2 they stay strings. If you want a real boolean, write `true`/`false`, otherwise your JSON gets `"yes"` not `true`.
Assuming comments survive the round-trip. JSON has no comment syntax, so every `# note` line is dropped when you convert YAML to JSON. Move anything important into an actual key before converting.

Privacy

Conversion runs entirely in your browser using the eemeli/yaml library. Whatever you paste, whether a Kubernetes secret manifest or a config with tokens, is parsed in the tab and never sent to any server. This tool does not write your YAML or JSON into the URL, so nothing sensitive ends up in browser history, share links, or referrer headers. Close the tab and it is gone.

FAQ

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YAML ⇄ JSON Converter — Both Directions, with Line-numbered Errors

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How YAML ⇄ JSON Converter fits into your work

Conversion jobs

Conversion checks

Good next steps

Real-world use cases

Pasting a Kubernetes manifest into a JSON-only API client

Reading a dense JSON config that a teammate sent

Converting a docker-compose snippet for a Node script

Sanity-checking GitHub Actions YAML indentation

Common pitfalls

Privacy

FAQ

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