Schema Labs

Documentation / Preview

A short guide to clearer checks.

Start with a schema and a payload. Move to revision review when the contract changes.

Start in the playground

  1. Open the playground and choose Validate payload.
  2. Use Load example, paste JSON, or open a local JSON file.
  3. Run the check. Each failed rule includes an instance path and a readable message.
  4. Choose Compare schemas to review a baseline and a candidate revision.
  5. Download the JSON report if you want to keep the results.

Payload validation

Ajv validates JSON Schema 2020-12 and draft-07 documents. Types, required fields, enums, local references, composition and supported format rules are evaluated by the validator. Inputs are not coerced and missing fields are not filled in.

schema.json
{
  "type": "object",
  "properties": {
    "total": { "type": "number", "minimum": 0 }
  },
  "required": ["total"]
}

For that schema, {"total":42.5} satisfies the contract. {"total":"42.5"} does not: a numeric string is still a string.

How revision findings work

Comparison is directional: the left document is the baseline, and the right document is the candidate. Checks identify structural changes that could reject data previously accepted by the baseline.

Breaking
A recognized rule became more restrictive.
Review
The effect needs a human decision.
Compatible
A recognized rule became more permissive.

Findings include JSON Pointer paths. Treat “compatible” as a local finding about that change, not a guarantee that the full API contract is compatible.

Supported scope & limitations

  • Validation accepts JSON, not YAML or a complete OpenAPI document.
  • Revision checks inspect common types, object properties, required fields, enums, additional properties and size/value bounds.
  • Changed advanced rules, including schema composition, may require manual review.
  • Remote references are never fetched. Only references resolvable within the document are supported.
  • Each editor accepts up to 512 KB of UTF-8 input. A timed-out worker is terminated.
  • No hosted CI integration, team account or AI interpretation is included in the preview.
  • We do not prove full semantic or API request/response compatibility.

Processing & reports

The worker receives documents from the page and returns computed results. There are no document upload requests. Refreshing the page clears your edits; use Download report before leaving if you want a record.

Reports contain findings, timestamps and mode information, not your full source documents. The website host still receives ordinary requests for site files. Read the privacy notice for that distinction.