🧩 JSON Formatter
Format, minify and validate JSON with clear error messages. 100% free, no signup — everything runs in your browser.
This free JSON formatter pretty-prints, validates and minifies JSON instantly in your browser. Paste a wall of unreadable single-line JSON from an API response or a log file, click Format, and get cleanly indented, readable output; click Minify to strip the whitespace back out for production payloads. If the JSON is invalid, you get a clear error message that tells you what went wrong — a missing comma, an unquoted key, a trailing bracket — instead of a silent failure. Everything runs locally: your JSON is never uploaded, which matters when the payload contains API keys, customer records or internal data. For developers, testers and anyone who touches APIs, a fast JSON validator is one of the most-used tools of the working day.
How to use
- Paste your JSON into the input box — an API response, a config file, a log entry, anything.
- Click Format to pretty-print it with 2-space indentation, the standard in modern codebases.
- Click Minify to compress it to a single line — ideal for production payloads and query strings.
- If the JSON is invalid, read the error message: it identifies the problem so you can fix the exact spot.
- Common culprits: a trailing comma after the last item, single quotes instead of double quotes, unquoted keys, or comments (JSON allows none of these).
- Copy the result and paste it back into your code, API client or config file.
Why use our json formatter?
The reason to use this formatter over pasting into random websites is privacy: formatting happens entirely in your browser, so API responses containing tokens, personal data or unreleased features never leave your machine. That makes it safe for exactly the payloads developers most often need to inspect. It is also fast on large documents — there is no upload round-trip, so even big API dumps format instantly.
Validation doubles as debugging. When a config file refuses to load or an API rejects your request body, pasting the JSON here pinpoints the syntax error in seconds — usually a trailing comma or single quotes. Formatting and minifying are one click each, so you can go readable-to-compact and back without touching your editor. When your debugging session widens, the neighbours help: decode a JWT segment or API payload with the Base64 encoder/decoder, normalize key names with the case converter, or fill test fixtures with values from the random number generator.
Who is this tool for?
Backend and frontend developers are the obvious audience — inspecting API responses, debugging webhook payloads, editing package.json or tsconfig files, and formatting fixtures for tests. QA engineers and testers validate request bodies before filing bug reports, and paste failing responses here to see structure at a glance. DevOps engineers untangle JSON logs and cloud configuration exports.
But JSON is no longer only a developer format. Data analysts receive JSON exports from analytics platforms and need them readable before conversion. Technical writers format example payloads for API documentation. Students learning web development use the validator to understand why their first fetch call fails. No-code builders wiring up Zapier, Make or Airtable automations hit raw JSON at every webhook step. Anyone who has ever been emailed a one-line JSON blob and asked to 'take a look' can turn it into something readable here in one click.
Frequently asked questions
No. Formatting, validation and minification all run locally in your browser — nothing is sent to any server. It is safe even for payloads containing keys, tokens or customer data.
Two spaces — the dominant convention in modern JavaScript and web projects. Minify removes all insignificant whitespace for the smallest output.
The most common causes: a trailing comma after the last element, single quotes instead of double quotes, unquoted property names, or // comments. Standard JSON allows none of these — the error message points you to the problem.
Yes. Because everything runs locally with the browser's native parser, even multi-megabyte JSON documents format quickly.
Formatting adds line breaks and indentation for human reading; minifying strips them for machines. The data is identical — only whitespace changes, so it is always safe to go back and forth.
Values are preserved exactly; keys keep the order they appear in your input. Only whitespace is added or removed.
This tool validates standard JSON, which is what APIs and most config parsers require. Remove comments and trailing commas first — or treat the error messages as a checklist of what to strip.