Schema validation workflow
Validate JSON against a schema before it ships
A schema catches shape problems that a plain formatter cannot see, such as a missing required field or a wrong data type.
Confirm structure, not just syntax
Valid JSON can still be the wrong shape. Check the schema before trusting the payload.
Paste the schema
Use an existing schema or a draft generated from a sample payload.
Paste the JSON data
Use a real example, including edge cases such as optional fields.
Review each error
Check the field path and the rule that failed.
Fix the data or the schema
Decide whether the payload or the schema definition is wrong.
What a schema validation report tells you
- The root type of the document
- Missing required properties
- Property values that violate type constraints
- Array items that do not match the item schema
- Values outside an allowed enum
Validate in three steps
- 1
Open the JSON schema validator and paste the document and the schema.
- 2
Run the validation and read each error with its JSON path.
- 3
Fix the document or the schema and re-validate until clean.
Common schema failures
- A required field is missing
- A number arrives as a string
- An enum value is not in the allowed list
- Nested objects do not match the expected shape
Keep schemas useful
- Mark only truly required fields as required
- Use enums for fixed value sets
- Version the schema alongside the API
- Validate real production samples, not just test fixtures
Frequently asked questions
Which schema draft is supported?
The validator implements the draft-07 vocabulary used by most APIs and configuration systems.
What happens with additional properties?
By default additional properties are allowed unless the schema sets additionalProperties: false.
Can I validate a document without a schema?
No. Validation compares a document against a schema. To create one from an example, use the schema generator first.
Is my data uploaded?
No. Both document and schema are processed locally.
Validation stays on the device
The schema check runs in the browser. Redact identifiers before sharing a failing example with a team.
Open JSON Schema Validator