JSON Validator
Validate JSON syntax and get clear, line-aware error messages so you can fix malformed JSON fast. Client-side only.
How it works
- 1
Paste your input
Type or paste your data into JSON Validator.
- 2
Adjust options
Tweak the available settings — the output updates as you type.
- 3
Copy the result
Copy the output to your clipboard or download it as a file.
Common uses
- Find the exact line breaking a malformed API response.
- Validate a config file before committing it.
- Confirm a webhook payload is well-formed JSON.
About the JSON Validator
Validate JSON syntax and get clear, line-aware error messages so you can fix malformed JSON fast. Client-side only.
JSON Validator is part of a free, privacy-first toolkit. Everything is computed instantly on the client, so your data never leaves the page — useful when you're working with sensitive payloads.
Because json validator works without any sign-up or installation, you can use it as often as you like and it's always available — on desktop or mobile, and even offline.
Explore more developer tools, or try JSON Formatter · JSON Minifier.
Related tools
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JSON Validator — FAQ
Invalid JSON returns the parser's message describing what's wrong so you can fix the offending character.