JSON Schema validator for payloads you shouldn’t upload

Syntax can pass while the shape is wrong. Paste instance JSON and a schema; see which paths fail. Runs client-side (AJV or equivalent) — useful when the sample contains secrets.

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Schema

Data

When to use

API contract checks, config gates before deploy, or teaching required vs optional fields when the sample may contain secrets you will not upload.

Examples

Input

schema: {"type":"object","required":["name"],"properties":{"name":{"type":"string"}}}
data: {"name":"DevKitBase"}

Output

Valid against schema

Input

schema: {"type":"object","required":["email"]}
data: {"name":"Ada"}

Output

Invalid — missing /email

How it works

Compiles the schema (AJV / draft-2020-12 path), validates the instance, lists instancePath + messages. Remote $ref fetch may be disabled for privacy — prefer inline/$defs.

Common pitfalls

Syntax can pass while the shape fails — run JSON Validator first if parse fails.
Draft support is finite; don’t claim “all drafts”.
Remote $ref URLs may not resolve in-browser by design.

How this differs

Schema = shape/types. JSON Validator = well-formed only. Formatter/minify don’t enforce contracts.

FAQ

Which draft is supported?

State the implemented draft clearly in How / FAQ (don’t claim “all drafts”).

Is this the same as syntax validation?

No — use JSON Validator for parse-only.

Can schemas reference remote `$ref` URLs?

Prefer inline/`$defs`; remote fetch may be disabled for privacy.

Security product?

No — developer debugging aid.

Runs in your browser. Nothing is uploaded. Not a security product —hashes and JWT decode are for debugging, not password storage or auth advice.