JSON Fixer · No upload · No signup

Format, validate,
explore.

Paste your JSON, get it pretty-printed, validated, or turned into a browsable tree. Syntax errors show exactly which line broke. Runs entirely in your browser — we never see your data, which matters when that data has API keys in it.

Indent
View
Input
Input: 0 chars 0 lines 0 B
Output
Output appears here after you paste JSON and click Format.
Output: 0 chars 0 lines 0 B

JSON, explained.

What's the "Format" button actually doing?

Parses your JSON into an object, then re-serializes it with consistent indentation and line breaks. Invalid JSON gets caught with a specific line/column error instead of the browser's vague "Unexpected token" message.

Why "Minify"?

Shrinks JSON by removing all unnecessary whitespace. A 2KB config file minifies to ~1.2KB. Useful when embedding JSON in URLs, HTML attributes, or anywhere that bytes matter. Same data, fewer characters.

What does "Sort keys" do?

Alphabetizes the keys in every object, recursively. Great for diffing two JSON files — once keys are sorted consistently, diff shows actual content differences, not just key-order noise.

Is tree view better than text?

Tree view is better for exploring JSON (click to expand/collapse nested parts, see item counts). Text view is better for copying or editing. Use whichever fits the task.

How big can my JSON be?

Browsers comfortably handle up to ~5MB. Beyond that, format/tree rendering slows down. At 50MB+, the browser might freeze. For giant JSON files, use command-line tools like jq instead.

Is anything uploaded?

No. The whole thing runs in your browser's JS engine. No server involved. We can't see your JSON because it literally never leaves your device. Which matters when you're pasting in a response that contains API keys, user data, or other sensitive content.