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JSON Schema Validator

Validate JSON documents against a schema and see exactly which rules fail.

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Contract checking for JSON

Syntax-valid JSON can still violate API contracts. CalcForge pairs your instance document with a JSON Schema and reports failing paths—required fields, type mismatches, enum violations—so you catch integration bugs before they reach production.

Good fits

  • Verifying webhook payloads against published schemas
  • CI-style manual checks on config files before deploy
  • Teaching schema keywords with immediate feedback
  • Debugging client payloads rejected by strict APIs
Schema: {"type":"object","required":["id"],"properties":{"id":{"type":"integer"}}}
Instance: {"id":"abc"}
Error: /id must be integer

Practical notes

  • Generate starter schemas from samples with JSON Schema Generator, then refine rules.
  • Draft versions (2019-09 vs 2020-12) differ—match the dialect your toolchain expects.
  • Validation runs locally; safe for schemas describing internal data models.

Frequently asked questions

Which JSON Schema draft is supported?

Common draft features used in OpenAPI and config tools are supported. Test edge keywords on your sample before relying on them in CI.

Can I validate YAML after converting?

Convert YAML to JSON first, then paste both schema and instance into the validator.

Does validation fix my JSON?

No—it reports failures only. Repair syntax separately, then adjust data to satisfy schema rules.

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