JSON Formatter

The JSON Formatter is a free online json formatter and json beautifier that turns raw or minified JSON into clean, properly indented output in seconds. It's built for the moments every developer hits constantly: pasting a squashed API response into a readable shape, reviewing a teammate's config file, or checking that a payload you're about to send actually parses. Front-end and back-end engineers, QA testers poking at API responses, and anyone maintaining JSON-based config files (package.json, tsconfig.json, OpenAPI specs) will find themselves reaching for it daily.

Beyond pretty-printing, the tool doubles as a strict json validator: invalid JSON — a missing comma, an unquoted key, a trailing bracket, a stray comment (JSON doesn't allow them) — is caught instantly, with an error message that names the problem instead of leaving you to scan character by character. Large, deeply nested payloads become much easier to scan once keys are sorted alphabetically, which is especially useful when diffing two versions of the same object or hunting for a specific field in a response with hundreds of keys. When you're done reviewing, the same tool can minify the JSON back down, stripping whitespace before it ships to production or gets embedded in a script tag.

Under the hood the formatter uses the browser's native JSON parser, so the validation you see here is exactly what JSON.parse would do in your own code — no approximated or lenient third-party parser papering over real errors. Formatting, minifying and key-sorting all happen instantly as you type or paste, with no network request and no size limit beyond what your browser's memory can hold, which makes it comfortable to use even on multi-megabyte API dumps.

Because everything runs client-side in JavaScript, sensitive payloads — auth tokens, customer records, internal API responses — never leave your device, which makes this a safe way to format json online even for data you wouldn't want to paste into a random third-party service.

Most parse errors come from JavaScript habits that JSON does not allow. JSON.parse is strict: it accepts double-quoted strings and keys, commas between items, and no comments or trailing commas. The table below pairs each common mistake with the corrected form.

If the syntax is valid but the shape is wrong, check it against a schema with the JSON Schema Validator. For tabular payloads, JSON to CSV turns an array of objects into spreadsheet rows, and CSV to JSON rebuilds JSON from a spreadsheet export.

JSON ignores whitespace between tokens, so indentation width never changes the data. Two spaces and four spaces are both valid; the choice is about readability and consistency, not correctness.

Use 2 spaces as the default for JavaScript and TypeScript projects, package.json, and deeply nested API responses. Narrow indentation keeps levels visible without pushing lines off-screen and fits the common style in the JavaScript ecosystem. Use 4 spaces when your repository, editor configuration, or team style guide already standardizes on 4. If a project has no convention, pick 2 and record it in .editorconfig so every editor agrees. If the same settings live in YAML, the YAML Formatter applies the same indentation discipline.

VS Code ships with a built-in JSON formatter, so no extension is required for a file with valid JSON. If the file contains comments or trailing commas, strict JSON mode reports them as errors before formatting. For Base64-encoded values inside a JSON file, decode them with Base64 before formatting the enclosing object. The VS Code JSON documentation lists the built-in formatter and its settings.