Free developer utility · No account · No upload
Check multiple JSON outputs against one JSON Schema before shipping API responses or AI-agent results. All validation runs locally in this browser.
Supported: type, required, properties, additionalProperties=false, items, enum, const, minimum, maximum, minLength, maxLength, pattern, minItems, and maxItems. Limits: one JSON value per non-empty line; object/array schema nodes only; no $ref/$defs, composition (allOf/anyOf/oneOf/not), format checks, boolean schemas, or additionalProperties schemas. Pattern uses this browser's JavaScript regular-expression engine. Unknown keywords are ignored. A PASS means only that the value matches the rules listed here, not that it is valid under the full JSON Schema specification. Use a full validator for production or security-critical contracts.
If this utility saves you time, you can optionally support future improvements with USDT. The tool remains free; payment does not unlock features or create a service obligation.
TYEEz4te11EYecrhNTFLY5enoMm7qPmjFd
0x48bf49eca7f6ef784ff524a8f58e156232746ca6
Important: select USDT and the exact same network. Crypto transfers are generally irreversible. Before sending, confirm the recipient's current receiving address and that the receiving service supports the selected network. Receiving addresses or supported networks may change. Never send until the details are confirmed.
This free tool checks a subset of JSON Schema rules. For a human-reviewed PASS/FAIL report across up to 10 redacted payloads, see the API & AI-Agent Contract Review (4 USDT; TRC20/BEP20 only; no card checkout), or read the free contract checklist.
Never send secrets, personal data, or confidential production payloads.