Free Developer Tool

Online JSON Formatter, Validator & Auto-Repair Engine

Prettify, validate and auto-repair JSON in your browser. Zero uploads, zero servers — every byte stays on your machine.

100% In-Browser & PrivateNo uploadsFree forever

MyJSONPal is a free online JSON formatter and validator built for developers who care about speed and privacy. Paste any JSON document into the editor and get a cleanly indented, color-highlighted result in milliseconds. Because everything runs in your browser through a Web Worker, your data is never transmitted, logged, or stored anywhere.

Beyond pretty-printing, the workspace doubles as a strict validator: syntax errors are highlighted inline with line and column positions, and the Magic Auto-Repair engine can fix common mistakes such as trailing commas, single quotes, unquoted keys, and Python-style True/False/None literals with a single click.

Once your JSON is clean you can minify it for production payloads, explore it as a collapsible tree, copy it to the clipboard, or convert it to CSV, YAML, TypeScript interfaces, or SQL INSERT statements — all offline.

How to format and validate JSON

  1. 1Paste your JSON into the left editor, or drag and drop a .json file anywhere on the input pane.
  2. 2Click Format (or press the switch to JSON) to pretty-print with two-space indentation and inline validation.
  3. 3If the validator reports errors, press Auto-Fix JSON to repair trailing commas, single quotes, and other common mistakes automatically.
  4. 4Switch to Tree View to explore nested structures, then Copy to Clipboard or Download the result.
  5. 5Use the format dropdown to convert your document to CSV, YAML, TypeScript or SQL in one click.

Why MyJSONPal is different

Privacy-first, by design

All parsing, validation and conversion runs in your browser. Your data is never sent, logged, cached or sold — close the tab and it is gone.

Fast, even on huge files

Heavy processing is offloaded to a Web Worker, so multi-megabyte documents are handled without freezing the interface.

No accounts, no limits

There is nothing to sign up for and no usage quota. Paste, format, convert and download as often as you like.

Frequently asked questions

Is my JSON uploaded to a server?

Never. MyJSONPal processes everything locally in your browser using JavaScript and Web Workers. There are no API calls, no analytics beacons, and no server-side storage — your data never leaves your device.

What does "format" do to my JSON?

Formatting re-parses your JSON and re-emits it with two-space indentation, consistent key ordering, and proper string escaping. It also validates the document at the same time and flags any syntax errors.

Can I use it offline?

Yes. Once the page is loaded, the tool is fully self-contained. You can paste data, format it, convert it, and download the results with no internet connection at all.

Is there a limit on file size?

Because processing happens in your browser, the practical limit depends on your machine. Large payloads are handled by a dedicated Web Worker so the interface stays responsive.

Is MyJSONPal really free?

Yes — free forever, with no accounts and no usage quotas. The tool is supported by unobtrusive advertising, so it stays free for everyone.

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