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
- 1Paste your JSON into the left editor, or drag and drop a .json file anywhere on the input pane.
- 2Click Format (or press the switch to JSON) to pretty-print with two-space indentation and inline validation.
- 3If the validator reports errors, press Auto-Fix JSON to repair trailing commas, single quotes, and other common mistakes automatically.
- 4Switch to Tree View to explore nested structures, then Copy to Clipboard or Download the result.
- 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.
How to format JSON?
Paste your JSON into the editor and click Format (or press the switch to JSON). MyJSONPal re-parses the document and re-emits it with two-space indentation, color highlighting, and inline validation — all instantly and entirely in your browser.
How to fix JSON error?
Press Auto-Fix JSON. The Magic Auto-Repair engine fixes the most common mistakes automatically — trailing commas, single quotes, unquoted keys and values, stray double quotes, and missing or extra commas. If anything remains, the validator highlights the exact line and column.
How to fix JSON parse error?
Run Auto-Fix JSON to repair common parse errors such as trailing commas, single-quoted strings, unquoted keys, unquoted values, and Python-style True/False/None literals. Any error the engine cannot fix is pinpointed with its exact line and column so you can correct it by hand.
How to fix unexpected end of JSON input?
This error usually means a closing brace, bracket, or quote is missing. Click Auto-Fix JSON first — it closes unclosed strings automatically — then check the reported line and column for any missing closing } or ] at the end of the document.
How to fix invalid JSON response?
Copy the response body into the input editor, click Auto-Fix JSON to repair common syntax issues, then Format to validate. For API responses the validator points to exactly where the invalid part begins, so you can patch the server output quickly.