JSON Schema
Generate schema output from sample JSON payloads. Free online developer tool for fast browser-based work.
What is this tool?
JSON Schema helps describe the expected shape of a JSON payload: required fields, primitive types, arrays, nested objects and allowed structures. Use it when readable JSON is not enough and you need a contract.
How to use
- Paste a representative JSON sample with reduced, fictitious or non-production values.
- Generate or inspect the schema structure, then review required fields and inferred types.
- Use the schema as a starting point for API validation, mocks, contract tests or documentation.
Practical example
A small user settings payload can become a schema draft that catches missing or mistyped fields later.
Sample:
{ "theme": "dark", "pageSize": 25, "alerts": true }
Schema focus:
- theme: string
- pageSize: number
- alerts: booleanAPI
The API documentation is the right place to connect schema workflows with repeatable request and response examples.
When to use
Related tools
Privacy
Use reduced examples instead of full production responses. Remove emails, customer records, tokens and internal identifiers before generating a schema.
Frequently asked questions
Is a generated JSON Schema always correct?
No. It reflects the sample you provide and should be reviewed before it is used in tests or documentation.
Can JSON Schema validate business rules?
It can validate structure and many value constraints, but business rules may still need application logic.
Should I generate a schema from production data?
Prefer a minimized, safe or scrubbed sample so confidential fields are not exposed.
Limitations / when not to use
A generated schema is a draft. Review optional fields, enum values, date formats and domain rules manually before treating it as a source of truth.