How to validate JSON
- Paste your JSON into the box above.
- Read the verdict. It says valid or invalid right away.
- Look at the line with the pointer if the JSON is invalid.
- Fix the error and watch the verdict update live.
- Check the structure stats once the JSON passes.
What this JSON validator gives you
- A clear valid or invalid verdict.
- The exact line and column of the first syntax error.
- The failing line with a caret under the bad character.
- A plain language cause for the error.
- A count of keys and objects plus depth once the JSON parses.
- Live checks as you edit.
Why are JSON errors so hard to find?
A parser message is accurate and almost useless. "Unexpected token in JSON at position 1847" gives you a character count inside what may be one giant line. Nobody can count to 1847.
It gets worse. The parser reports where it noticed the problem. That is often not where the problem is. A missing closing brace on line 12 goes unnoticed until the parser runs out of text. So it reports the last line. The real fault sits a hundred lines earlier.
How this JSON validator helps
The tool turns the character count into a line and column. It prints the lines around the error. It places a caret under the exact character. An abstract number becomes a spot you can see.
It also looks at the characters around the failure. It does not just repeat the engine's wording. Engine messages differ between browsers. The tool calls a comma right before a closing brace a trailing comma. It calls a single quote near the error a quote problem.
The five errors behind almost every failure
| Error | What it looks like |
|---|---|
| Trailing comma | A comma after the last item before } or ] |
| Single quotes | 'name' instead of "name" |
| Unquoted keys | {name: 1} |
| Unclosed bracket | Reported at the end of the file |
| Comments | // note or /* note */ |
Modern JavaScript encourages trailing commas for cleaner code diffs. That habit sneaks into JSON files where it fails. Some tools accept comments in JSON as an extra. That is worse. The file works on your machine and fails somewhere else.
Valid syntax is not the same as correct data
This JSON validator checks syntax. It confirms the document is well formed. It cannot tell you if the structure matches what an API expects. It cannot spot a missing required field or a wrong value type. That job belongs to schema validation, usually with JSON Schema.
The structure summary helps a little. An API response should hold twelve keys and the count says nine? A field is missing no matter what the syntax check says.
How to fix the most common JSON errors
- Search for a comma right before a closing brace or bracket. Delete it.
- Replace single quotes with double quotes around keys and strings.
- Wrap every key in double quotes.
- Delete any comment lines.
- Count opening and closing braces when the error points at the end.
Tips to keep JSON valid
- Let a program write JSON for you instead of typing it by hand.
- Turn off trailing commas in your editor for JSON files.
- Save config files with a .json name so editors check them.
- Validate before every deploy and not after a crash.
- Keep one small change per edit so errors stay easy to find.
A habit of quick checks saves hours later. A broken config often fails at night on a live server. A two second check stops that.
What the error messages mean
The tool names the cause in plain words. "Unexpected end" means a bracket never closed. "Unexpected token" means a stray character sits where a value should be. "Bad string" often means a line break or a raw tab inside quotes. Each note points you to the fix.
Who uses a JSON validator?
Developers check config files before a deploy. QA testers check API payloads. Students check homework that uses JSON. DevOps teams check pipeline settings. No code writers check exports from no code tools.
Related JSON tools
Want readable output once it passes? Use the JSON formatter. Need a smaller payload? Try the JSON minifier. Want to compare two files? Sort keys with the JSON beautifier. Want to test a pattern inside a value? The regex tester helps.
Your data stays private
The tool parses everything in your browser. Documents with passwords, keys or personal data never leave your device.