TOML to JSON Converter — Free Online TOML Parser & Viewer

TOML to JSON Converter — Free Online TOML Parser & Viewer. Free TOML to JSON converter: paste or upload a TOML file (Cargo.toml, pyproject.toml, config.toml) and get clean, formatted JSON with syntax errors, line numbers, sorting and download.

Our TOML to JSON converter turns any TOML document into clean, valid JSON instantly.

Paste your configuration or upload a .toml file — Cargo.toml, pyproject.toml, config.toml, Hugo or Netlify settings — and the online TOML parser maps every table, inline table, array of tables, string, integer, float, boolean and date to the equivalent JSON structure.

It is the quickest way to convert TOML to JSON for REST APIs, JavaScript and TypeScript projects, jq pipelines or any tool that only reads JSON, and to inspect a TOML file as a readable JSON tree.

The converter follows the TOML v1.0 specification: offset date-times become ISO 8601 strings, local dates stay 1979-05-27, and values JSON cannot represent — 64-bit integers beyond JavaScript's safe range, inf and nan — are kept as strings instead of being silently corrupted.

Choose 2, 3 or 4 spaces, tabs or minified output, and sort keys alphabetically for stable diffs.

If the TOML is invalid you get the parser message with the exact line and column, so this TOML to JSON online tool also works as a quick syntax check; statistics show how many keys, tables and arrays the document contains. Going the other way?

Use JSON to TOML, or convert the same file with TOML to YAML. Everything runs locally in your browser — private registry URLs, credentials and deployment settings in your TOML files are never uploaded.

Copy the JSON with one click, download it as converted.json, or share a link that restores your input and options. Related tools: JSON Formatter, JSON Viewer, JSON Compare, YAML to TOML and YAML to JSON.

Frequently asked questions

How do I convert TOML to JSON?

Paste TOML into Your TOML, or click Upload .toml file to load one such as Cargo.toml or pyproject.toml. The JSON appears on the right as you type. Click Copy JSON, or Download .json to save it as converted.json. Load sample shows an example.

How are TOML dates, big integers, inf and nan converted?

JSON has no date type, so date-times become ISO 8601 strings and local dates stay as text such as 1979-05-27. Integers too large for JavaScript to hold exactly and the special floats inf, -inf and nan are written as strings, so no value is silently changed.

What indentation and sorting options are there?

Indent offers 2, 3 (the default) or 4 spaces, Tab, or Minify for single-line JSON. Sort keys orders object keys alphabetically at every level, which gives stable output for diffs; arrays keep their original order.

Why do I get an Invalid TOML error?

The parser follows the TOML 1.0 specification and reports the first problem with its line and column, such as an unquoted string, a duplicate key or a table defined twice. Fix that line and the JSON appears again. Valid input shows a Valid TOML badge plus key, table and array counts.

Is my TOML file uploaded to a server?

No. Files you upload are read by your browser and parsed locally, so registry URLs, tokens or settings in your config stay on your device. Only Copy link puts your input into a URL, and only when you click it.

How to use this online tool

TOML to JSON Converter — Free Online TOML Parser & Viewer is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.

Private processing in your browser

TOML to JSON Converter — Free Online TOML Parser & Viewer keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.

When this tool is useful

Use TOML to JSON Converter — Free Online TOML Parser & Viewer for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.

Practical tips

Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.