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JSON Formatter

Format, validate, and minify JSON online. Free, no signup — your data never leaves your browser.

Free No signup Client-side Privacy friendly Updated

Input

⌘↵ format · Esc exit fullscreen

How to use

  1. 1 Paste your JSON into the input panel on the left.
  2. 2 Pick indent size (2, 4, or tab) and toggle Sort keys if needed.
  3. 3 View the formatted, minified, or tree output on the right. Copy or download with one click.

Features

Beautify & minify

Pretty-print with 2/4-space or tab indentation, or minify to the smallest valid payload.

Real-time validation

Instant syntax checking with the exact line and column of any error.

100% private

Runs entirely in your browser — your JSON is never uploaded to a server.

Tree view & key sort

Collapsible tree for large payloads and recursive alphabetical key sorting.

Common use cases

  1. 1

    Debug API responses

    Paste a raw API payload to read it clearly and spot malformed or missing fields.

  2. 2

    Clean up config files

    Reformat hand-edited JSON config with consistent indentation before committing.

  3. 3

    Shrink payloads

    Minify JSON to cut size before sending it over the network or embedding it in code.

Example

Input

{"name":"Zerethon","tools":["json","sql"],"free":true}

Output

{
  "name": "Zerethon",
  "tools": [
    "json",
    "sql"
  ],
  "free": true
}

Frequently asked questions

Is this JSON formatter really free?

Yes — completely free. No signup, no ads, no rate limits. The formatter runs in your browser so your data never reaches our servers.

How large a JSON file can it handle?

Up to ~10 MB efficiently. For very large payloads, paste in chunks or use a streaming parser.

Does it validate JSON syntax?

Yes — real-time validation. When parsing fails, the error includes a line and column so you can jump straight to the problem.

Can I sort object keys alphabetically?

Yes. Toggle "Sort keys" in the settings bar. The sort is recursive — nested objects are sorted too.

What about minification?

Switch the output to Minified to strip all whitespace. Useful for reducing payload size before transport.

Can I resize the input and output panels?

Yes — drag the divider between the panels on desktop. Double-click the divider to reset to a 50/50 split. Each panel also has a fullscreen toggle.

What is JSON Formatter?

A JSON Formatter is a tool that converts compact or minified JSON data into a structured, indented form for readability, and reverses the process for transmission. It validates syntax against RFC 8259 / ECMA-404, detects errors with line and column positions, and renders output as pretty-printed text, minified text, or a collapsible tree.

How JSON Formatter compares to alternatives

JSON Formatter versus typical browser and desktop alternatives — features compared at a glance.
Feature Zerethon Tools Typical online tools Desktop apps
Signup required No Sometimes Sometimes
Data leaves device No Yes (server-side) No
Free Yes Yes (with ads) Sometimes paid
Works offline Yes (after load) No Yes
Max input size ~10 MB 1–5 MB Unlimited
Tree view Yes Sometimes Yes
Error line + column Yes Sometimes Yes
Summary

JSON Formatter is a free developer utility by Zerethon Tools. Format, validate, and minify JSON online. Free, no signup — your data never leaves your browser. Runs entirely in the browser — no signup, no upload.

Category
Developer
Pricing
Free
Privacy
Browser-based
Signup
Not required

Privacy

Your data never leaves your browser unless explicitly stated. JSON Formatter runs entirely client-side — no server upload, no logging, no tracking of your input.

Compare

JSON vs YAML JSON vs XML CSV vs JSON

Learn the basics

What is JSON?

How-to guides

How to convert json to yaml

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