JSON Validate API - Free Syntax Checker
Parses a JSON string and reports whether it is valid. If invalid, the response includes the error message with the position of the syntax problem so you can fix it.
Code examples
curl -X POST https://api.botoi.com/v1/json/validate \
-H "Content-Type: application/json" \
-d '{"json":"{\"name\": \"botoi\", \"active\": true}"}'When to use this API
Validate user-submitted JSON in forms
Check that JSON pasted into a configuration form is syntactically correct before saving, giving users immediate feedback.
Gate CI deployments on valid config files
Call this endpoint in a pre-deploy hook to block deployments if any JSON config file has a syntax error.
Sanitize webhook payloads
Validate incoming webhook bodies to confirm they are parseable JSON before routing them to downstream processors.
Frequently asked questions
Does this check only syntax or also schema?
This endpoint checks syntax only. For schema validation against JSON Schema, use the /v1/schema/validate endpoint.
What error details are returned for invalid JSON?
The response includes the parser error message and the character position where parsing failed.
Can I validate JSON5 or JSONC (JSON with comments)?
No. This endpoint validates strict JSON per RFC 8259. Comments and trailing commas are flagged as errors.
Is there a size limit on the JSON input?
The maximum request body size is 1 MB. For larger documents, validate locally.
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