What TOML features does this converter support?

This converter handles all TOML 1.0 value types: basic strings (with escape sequences including \uXXXX and \UXXXXXXXX), literal strings, multiline variants of both, integers (decimal, hex 0x, octal 0o, binary 0b, with _ separators), floats (including inf and nan), booleans, offset datetimes, local datetimes, local dates, and local times. It also supports dotted keys, standard tables [section], and arrays of tables [[section]]. Inline tables and arrays (including nested arrays) are fully supported.

What happens to TOML date and time values in the JSON output?

JSON has no native date or datetime type, so TOML datetime, local date, and local time values are converted to strings in the JSON output. For example, the TOML value 1979-05-27T07:32:00Z becomes the JSON string "1979-05-27T07:32:00Z". If you need a JavaScript Date object, pass the string through new Date() in your code after parsing the JSON.

Does this work with Cargo.toml and pyproject.toml files?

Yes. Cargo.toml and pyproject.toml are standard TOML files and this converter handles them fully. Arrays of tables like [[bin]] and [[example]] in Cargo.toml become JSON arrays of objects. The [package], [dependencies], and [dev-dependencies] tables become JSON objects. Dotted keys such as package.version in the key position are resolved into nested objects in the JSON.

Can I convert TOML back to JSON and round-trip my data?

A TOML-to-JSON conversion preserves all data that JSON can represent. Strings, numbers, booleans, arrays, and nested objects round-trip cleanly. The only information lost is that TOML datetime values become plain JSON strings (JSON has no date type) and TOML comments are discarded (JSON has no comment syntax). If you need the reverse direction, use the JSON to TOML converter to go back.

My TOML has a parse error — what does the error message mean?

The error message includes the line number where parsing failed, for example "line 7: duplicate key". Common causes are duplicate keys (TOML forbids redefining a key in the same table), an unterminated string (missing closing quote), a tab character inside a basic string without the \t escape, or an invalid date literal. The line number in the error points to the problem line directly.

Inspect a Cargo.toml or pyproject.toml dependency tree

You receive a Cargo.toml with dozens of [dependencies] entries and want to pipe it through jq or feed it to a script that only reads JSON. Paste the file here, copy the JSON output, and process it with any JSON-capable tool without writing a TOML parser yourself.

Debug Hugo or Netlify config key paths

Hugo's config.toml and netlify.toml use nested tables that can be hard to trace visually. Paste the config into this converter and read the JSON to confirm that the key path your template references (e.g. .Params.footer.links) actually exists at that nesting level.

Convert TOML fixture data for unit tests

You want your test fixtures in JSON but the source data is in TOML (common when testing Rust or Python projects). Paste the TOML fixture here, copy the JSON, and drop it into your test suite. Arrays of tables become JSON arrays of objects with a predictable structure your test assertions can rely on.

Learn TOML by comparing it to JSON

If you know JSON but TOML table headers and array-of-tables syntax still confuse you, paste a small TOML file you encounter in the wild and read the JSON it produces. Seeing [[servers]] become a JSON array of objects makes the structural model clearer than reading the spec.

TOML to JSON Converter — Full TOML 1.0, Line-numbered Errors

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

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

Indent (spaces)

TOML input

JSON output

Paste TOML on the left to see JSON here.

What this tool does

Free online TOML to JSON converter. Paste any valid TOML — from Cargo.toml, pyproject.toml, Hugo config, or any .toml file — and get pretty-printed JSON out instantly. Supports all TOML 1.0 value types: basic and literal strings (including multiline), integers, floats, booleans, datetimes, arrays, inline tables, standard tables [section], and arrays of tables [[section]]. Parser errors include the line number so you can fix problems without guessing. Configurable JSON indent. One-click copy and download. Everything runs in your browser — nothing is uploaded to any server.

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 + Download; 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: Shareable URL state; Key settings are encoded in the URL so another person can reopen the same setup.
Performance budget: Initial JS <= 22 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 TOML to 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

Inspect a Cargo.toml or pyproject.toml dependency tree
You receive a Cargo.toml with dozens of [dependencies] entries and want to pipe it through jq or feed it to a script that only reads JSON. Paste the file here, copy the JSON output, and process it with any JSON-capable tool without writing a TOML parser yourself.
Debug Hugo or Netlify config key paths
Hugo's config.toml and netlify.toml use nested tables that can be hard to trace visually. Paste the config into this converter and read the JSON to confirm that the key path your template references (e.g. .Params.footer.links) actually exists at that nesting level.
Convert TOML fixture data for unit tests
You want your test fixtures in JSON but the source data is in TOML (common when testing Rust or Python projects). Paste the TOML fixture here, copy the JSON, and drop it into your test suite. Arrays of tables become JSON arrays of objects with a predictable structure your test assertions can rely on.
Learn TOML by comparing it to JSON
If you know JSON but TOML table headers and array-of-tables syntax still confuse you, paste a small TOML file you encounter in the wild and read the JSON it produces. Seeing [[servers]] become a JSON array of objects makes the structural model clearer than reading the spec.

Common pitfalls

Indenting TOML with tabs inside strings. TOML strings allow literal tabs, but the file's structural indentation must use spaces. If your editor auto-inserts tabs, the parser may trip on them in unexpected places — switch your editor to soft tabs for .toml files.
Forgetting that duplicate keys are fatal. Unlike JSON parsers that silently take the last value, TOML treats a duplicate key as a hard parse error. If the converter reports "duplicate key", search the file for every occurrence of that key name.
Defining a [table] after [[array.of.tables]] with the same base path. Once [[servers]] defines an array, writing [servers] later in the same file is a type conflict — use [[servers]] for every element, or restructure the data.

Privacy

The TOML parser runs entirely in your browser tab as plain JavaScript. Your TOML content, the parsed data, and the JSON output never leave the page and nothing is logged. The shareable link encodes your input in the URL query string, so if you paste that link into a chat or email, the recipient's server access log will record the TOML content. For secrets or private config, use the copy button and share the text separately instead of sharing the URL.

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TOML to JSON Converter — Full TOML 1.0, Line-numbered Errors

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How TOML to JSON Converter fits into your work

Conversion jobs

Conversion checks

Good next steps

Real-world use cases

Inspect a Cargo.toml or pyproject.toml dependency tree

Debug Hugo or Netlify config key paths

Convert TOML fixture data for unit tests

Learn TOML by comparing it to JSON

Common pitfalls

Privacy

FAQ

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