OpenAPI 3.0 Sample Spec (Backed by a Live API)

A complete OpenAPI 3.0 spec — paths, components, security schemes, examples — and a live API behind it. Use it to evaluate importers, generate clients, or learn the spec by reading a real-world example.

Get the spec

What's inside

• ~30 paths covering CRUD on users, products, orders, posts
• Reusable components — schemas, parameters, responses, examples
• Security schemes — Bearer JWT, API Key, OAuth2 client-credentials
• Discriminated responses — success/error envelopes with proper status codes
• Realistic examples on every request and response

Generate a client in seconds

# Python
openapi-generator-cli generate -i https://demo.totalshiftleft.ai/openapi.json -g python -o ./py-client

# TypeScript
openapi-generator-cli generate -i https://demo.totalshiftleft.ai/openapi.json -g typescript-fetch -o ./ts-client

# Go
openapi-generator-cli generate -i https://demo.totalshiftleft.ai/openapi.json -g go -o ./go-client

Test your OpenAPI tooling

Building an OpenAPI importer, validator or codegen tool? Point it at this spec — it intentionally exercises tricky features: oneOf responses, nullable fields, parameter style variations, and multiple security schemes per operation.

Frequently asked questions

Is the OpenAPI spec hand-written or generated?

Generated from the Fastify route schemas at runtime, so it always matches the live API exactly.

Can I download the spec?

Yes — /openapi.json or /openapi.yaml. Both are versioned with a stable URL.

Does it cover authentication?

Yes — Bearer JWT, API Key (x-api-key) and OAuth2 client-credentials are all defined as security schemes.

Other free public APIs in this sandbox

Topics: OpenAPI 3.0 example · sample OpenAPI JSON · OpenAPI for testing · OpenAPI tutorial · OpenAPI generator · free OpenAPI spec