JWT to OpenAPI Schema Generator

Paste a decoded JWT JSON payload to generate an OpenAPI 3.0 Schema Object or JSON Schema. 100% client-side.

Last reviewed: April 2026
Reviewed by , software engineer · last updated April 2026

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JWT Payload (JSON)
Generated Schema
Paste a JWT payload JSON object above to generate the schema.

How to Use the JWT to OpenAPI Schema Generator

To use the JWT to OpenAPI Schema Generator, follow these steps:

1. Decode your JWT - use our JWT Decoder or copy the payload section directly (the middle part of the three dot-separated segments, Base64-decoded to JSON).

2. Paste the payload JSON into the left panel.

3. Choose your output mode - OpenAPI 3.0 YAML schema, standalone JSON Schema, or a $ref pointer for inline referencing.

4. Copy or download the generated schema and paste it into your API specification document.

When to Use the Tool in Real Workflows

Use the JWT to OpenAPI Schema Generator when building REST APIs that accept or return JWT claims. This includes endpoints like /auth/token, /userinfo, or webhook event payloads. The tool automates type inference from a real token, saving significant time when documenting these endpoints.

How It Works

The JWT to OpenAPI Schema Generator works by parsing the JWT payload JSON and inferring the data types of each claim. It then generates an OpenAPI 3.0 Schema Object or JSON Schema based on these types. The generator supports various data types including strings, numbers, booleans, arrays, and objects. It also handles null values and standard JWT claim annotations with descriptions.

Tips, Edge Cases, or Limitations

1. The tool is 100% client-side, meaning your JWT payload never leaves your browser. This ensures privacy and security.

2. The generator supports both OpenAPI 3.0 YAML and JSON Schema formats. Choose the format that best fits your needs.

3. For complex JWT payloads, the tool may not be able to infer all types accurately. In such cases, manual adjustments may be required.

4. The tool does not support custom claim types that are not registered in RFC 7519. These claims will not be annotated with descriptions.

Frequently Asked Questions

An OpenAPI Schema Object is a JSON object that describes the structure of data exchanged in an API. It defines the data types, properties, and constraints for the data.
OpenAPI Schema is a dialect of JSON Schema Draft 07 with additional features specific to API documentation. It includes proprietary extensions like discriminator and xml, and uses nullable: true instead of type: ["string", "null"].
No, your JWT payload never leaves your browser. The tool processes the payload client-side, ensuring privacy and security.
The tool infers the data types of JWT claims using JavaScript's typeof operator and Array.isArray(). It supports various data types including strings, numbers, booleans, arrays, and objects. It also handles null values and standard JWT claim annotations with descriptions.
Yes, you can use the generated schema in your Swagger/OpenAPI document. The tool supports both OpenAPI 3.0 YAML and JSON Schema formats, making it easy to integrate into your API documentation.

Quick reference

JWT to OpenAPI Schema Generator Quick Reference
JWT Claim OpenAPI Property Data Type Example Value
iss issuer string https://example.com
exp expiration integer 1698765432
sub subject string user123
nbf notBefore integer 1698765432
iat issuedAt integer 1698765432
jti jwtId string abc123xyz