Contracts developers can use
Developer Stacks API
Developers need more than a working endpoint. They need predictable request formats, understandable errors, clear authorization rules, and a way to evolve integrations without surprises. This guide connects API contracts with local tooling, review practices, and the operational details that make a service straightforward to build against.
Make the interface a shared agreement
Begin an API design with the work a consumer needs to complete. Name resources consistently, define which operations can change state, and specify how invalid input is reported. Include examples of a successful request and a failure that the client can handle. An endpoint description is incomplete if it shows only the happy path.
The OpenAPI Specification provides a language-independent way to describe HTTP APIs, including paths, operations, schemas, and security requirements. An interface description helps teams agree on the contract. It does not replace implementation checks, authorization decisions, or the documentation of business rules that cannot be expressed by field types alone.
Build the workflow around the contract
Keep the interface description beside the implementation and review them together. Give consumers stable examples that contain invented demonstration data, never production credentials or personal records. Make the local startup process explicit: required runtime, dependency installation, environment settings, and the command that verifies the project is ready.
Treat error behavior as part of the developer experience. Explain what the caller can correct, what can be retried, and what requires support. For operations that create records or trigger jobs, decide how repeated requests should behave. A timeout can leave a client uncertain about whether work completed; the design should account for that uncertainty.
Keep security boundaries visible
Authentication establishes who or what is calling. Authorization decides whether that caller can perform the requested action on the requested resource. Describe both. An example that proves a user can sign in does not prove that one customer's records are protected from another customer's requests.
Plan changes from the consumer's perspective. Renaming a field, changing a value's meaning, or tightening accepted input may require coordination even if the server still starts successfully. Maintain a change log that explains behavior, provide a migration path when needed, and identify who receives deprecation notices.
Evaluate the first integration
Ask a developer unfamiliar with the service to follow the setup instructions and complete one realistic operation. Watch where they need undocumented knowledge. Turn those points into clearer examples, contract rules, or tooling. This exercise often reveals integration costs that a feature list misses.