JSON Validator
Validate JSON and pinpoint errors by line and column. Runs in your browser, no server.
ValidateLintClient-sideUnlimited
0 / 500,000
How to use
- Paste your JSON. Drop any JSON into the input box.
- Read the verdict. Green pass or red fail with exact error location.
Common use cases
- Debugging broken API responses
- Checking config files before deploying
- Learning JSON syntax rules
Frequently asked questions
- What does the JSON validator check?
- It parses the input against the strict JSON specification (RFC 8259 / ECMA-404) and reports the first syntax error with line and column. It does not validate against a JSON Schema.
- Why is my JSON invalid even though it looks fine?
- The most common causes are trailing commas after the last item, single quotes instead of double quotes around strings, unquoted object keys, and stray comments. Strict JSON disallows all of these.
- Does this validator support JSON5 or JSONC?
- No. JSON5 (which allows trailing commas, comments, and single quotes) and JSONC (JSON with comments) are intentionally rejected to stay aligned with the strict JSON spec.
- Is the JSON I paste sent to a server?
- No. Validation runs in your browser using JSON.parse, so sensitive payloads stay on your device.
Related tools
How to use
- Paste your JSON. Drop any JSON into the input box.
- Read the verdict. Green pass or red fail with exact error location.
Common use cases
- Debugging broken API responses
- Checking config files before deploying
- Learning JSON syntax rules
Frequently asked questions
- What does the JSON validator check?
- It parses the input against the strict JSON specification (RFC 8259 / ECMA-404) and reports the first syntax error with line and column. It does not validate against a JSON Schema.
- Why is my JSON invalid even though it looks fine?
- The most common causes are trailing commas after the last item, single quotes instead of double quotes around strings, unquoted object keys, and stray comments. Strict JSON disallows all of these.
- Does this validator support JSON5 or JSONC?
- No. JSON5 (which allows trailing commas, comments, and single quotes) and JSONC (JSON with comments) are intentionally rejected to stay aligned with the strict JSON spec.
- Is the JSON I paste sent to a server?
- No. Validation runs in your browser using JSON.parse, so sensitive payloads stay on your device.