JSON Validator
Validate JSON syntax and pinpoint errors instantly.
Processed locally in your browser. Nothing you enter is uploaded or stored.
- Free — no signup, no account, no watermark
- Runs entirely in your browser — nothing is uploaded to a server
- Works on mobile, tablet and desktop
- Instant — results appear as soon as you enter your input
Why this is private
- Processed locally in your browser. Nothing you enter is uploaded or stored.
- Open your browser's DevTools → Network tab while using this tool — you won't see a request carrying your input, because it never leaves your device.
- Nothing you enter is uploaded to a server or shared with us — the processing happens entirely on your device.
Overview
Checks whether a JSON document is syntactically valid and, if not, tells you exactly which line and character to fix.
How to use it
- 1Paste your JSON into the editor.
- 2Validation runs automatically as you type.
- 3If invalid, the exact error position is highlighted with a description.
Tips
- A single missing comma or extra closing brace is the most common cause of invalid JSON — check the line right before the reported error too.
Frequently asked questions
What people use it for
Debug a rejected API request bodyPaste the payload your client is sending to find the exact character the server is choking on.
Check a config file before deployingValidate package.json, tsconfig.json or a CI config so a stray comma doesn't break the build.
Verify JSON copied from logs or a chatPasted JSON often loses a bracket or gains smart quotes — this points straight at the break.
Related guides
- JSON parse errors explained: 'Unexpected token', 'Expected comma or brace', and the restWhat each common JSON error message actually means, the usual cause, and how to find the spot fast using line and column.
- How to format JSON (and actually understand the errors)JSON looks like a JavaScript object but follows stricter rules. Here's what those rules are and how to read the errors when they're broken.
- How to read JSON with a tree viewerA tree viewer turns a wall of brackets into a structure you can expand, search and copy paths from. Here's how to use one effectively.
Related tools
All developer toolsJSON Viewer & FormatterView, format, validate, edit and beautify JSON with an interactive tree view, plus a shareable link.JSON MinifierStrip whitespace to compress JSON to its smallest size.JSON DiffCompare two JSON documents and highlight the differences.Regex TesterTest regular expressions against sample text, with live matches, a replace mode, and Python/PCRE syntax support.
Ready to use JSON Validator?
JSON Validator