JSON Validator
Check JSON for errors and see the exact line and column of the problem.
Validate your JSON
About this tool
Paste JSON or open a .json file and press Validate. If it is valid, you see how many objects, arrays and values it holds and how deeply it is nested. If not, you get a plain-English message such as "Expected a comma or } after a value" with the line and column, and the text jumps to the problem so you can fix it straight away.
The validator follows the JSON standard (RFC 8259) strictly: comments, trailing commas, single quotes and unquoted keys are reported as errors, because most programs reject them. It also warns about duplicate keys, which the standard allows but which are usually a mistake. Everything runs in your browser and nothing is uploaded.
How it works
- Paste or open JSONPaste text, or open a .json file up to 10 MB.
- ValidatePress Validate to check the whole document.
- Fix and check againJump to the error, correct it and validate again.
Questions people ask
What does the validator check?
Why is a duplicate key only a warning?
Is my data sent anywhere?
Understanding validation errors
Look just before the position
The position marks where the checker gave up. The real mistake, such as a missing comma or quote, is often at the end of the line before.
Comments mean JSONC or JSON5
Files such as tsconfig.json or VS Code settings allow comments and trailing commas. They are not standard JSON, so remove those parts before using the data elsewhere.
Duplicate keys hide data
When the same key appears twice in an object, most programs keep only the last value. Rename or merge the duplicates the validator lists.