Design endpoints around business operations
An API should expose understandable operations and data rather than mirroring database tables blindly. Requests need validation, consistent responses and clear error handling so consuming applications know what happened.
Versioning becomes important when several clients depend on the same API. A mobile application may not update at the same moment as the website, so breaking changes need a migration strategy.
Third-party integrations need defensive development
External services can time out, reject credentials, change limits or return incomplete data. Payment gateways, mapping platforms and CRMs each have their own behaviour. We handle failures without assuming every request succeeds on the first attempt.
Secrets and API keys belong in secure configuration rather than public code. Permissions should be limited to what the integration actually needs, and webhook or callback requests should be verified where the provider supports it.
APIs can create a foundation for future channels
When business logic is centralized behind a documented API, a web application, mobile app and internal dashboard can share the same calculations and records. That can reduce inconsistent behaviour across channels.
Documentation, test environments and representative sample requests make an API easier for future developers to use.
Authentication should match who consumes the API. A private server-to-server integration has different needs from a public mobile application or partner API. Tokens need appropriate lifetimes and scopes, while sensitive operations may require stronger controls. Usage logging can help diagnose integration problems and identify unexpected traffic without recording confidential request data unnecessarily. When providers publish sandbox environments, we use them to test failure cases before production credentials are introduced.
Performance expectations should also be realistic. APIs serving interactive applications may need pagination, caching or background processing for expensive operations. We measure where delays occur before adding infrastructure, keeping straightforward requests simple while giving heavier workflows an appropriate execution model.
For integrations that affect money or reservations, idempotency can prevent a repeated request from creating the same action twice. This matters when a browser retries or a network connection is interrupted.