Integration begins with interfaces, and REST remains the lingua franca between enterprise systems. Well-designed REST is less about HTTP trivia and more about modeling stable resources and writing contracts that other teams can build against with confidence.
Modeling Resources Instead of Functions
Expose nouns that represent business state: customers, invoices, shipments. Actions become state transitions on those resources, so approving an invoice is a POST to its approvals collection rather than a callApprove endpoint. This style keeps the interface stable while internals change, and it gives integrators a predictable grammar: collections, items, and standard verbs behaving consistently everywhere.
Status Codes Errors and Pagination as Contract
Integrators spend most of their time on the unhappy paths, so specify them. Use precise status codes, return a consistent machine-readable error body with a code, message, and correlation identifier, and standardize pagination, filtering, and sorting parameters across every endpoint. An API where errors and lists behave uniformly cuts partner onboarding time more than any clever feature.
OpenAPI as the Source of Truth
Write the OpenAPI document first and review it like code. From that single artifact you can generate server stubs, client SDKs, mock servers for parallel development, and reference documentation. Contract tests in the pipeline compare the running service against the spec, catching drift before a partner does. The spec becomes the meeting point between teams that never share a codebase.
Action Step
Design an OpenAPI spec for a two-resource API, including error schema and pagination parameters. Generate a mock server from it with any OpenAPI tool and make three test calls, noting anything ambiguous you had to guess.
Educational content only. System and continuity designs must be validated against your own organization’s requirements, testing, and current vendor documentation. This course does not certify anyone.