An application programming interface, or API, is a defined way for software systems to request data or actions from one another. The interface specifies available operations, required inputs, returned outputs and failure behavior without requiring the consumer to know the provider’s internal implementation.
What does an API define?
- Endpoints, operations or events
- Request and response schemas
- Authentication and authorization
- Status codes and error messages
- Limits, pagination and retry behavior
- Versions and deprecation policy
How is an API used in commercial operations?
An API can create quotations, retrieve prices, synchronize suppliers, submit payment instructions or return transaction status. The consuming system should retain its own business reference and reconcile accepted requests with later status events.
API vs. webhook
An API request is commonly initiated by the consumer to retrieve or change data. A Webhook sends an event from the provider to a registered destination. Reliable integrations often use API calls for commands and webhooks for asynchronous changes.
What should implementers verify?
Confirm field meaning, currency precision, time zones, idempotency, permissions, rate limits and retry rules. An HTTP success response may mean that a request was accepted, not that the underlying payment or business process is complete.
