Application programming interface integration implements the authentication, requests, response handling, data mapping, retries, and error behavior needed to use another service. The integration translates between the external API contract and the application's internal data and workflow requirements.
A production integration should protect credentials, validate untrusted responses, respect rate limits, avoid duplicate side effects, and preserve useful diagnostics. Clear ownership is important because changes to either side of the contract can affect the workflow.
ELI5
Application programming interface integration connects two software systems through a defined set of requests and responses. It lets one application use data or actions supplied by another without a person copying everything by hand.
For example, an online shop can ask a delivery service's API for a shipping price and show the result during checkout. The integration must protect its credentials, check the response, and avoid creating duplicate shipments when a request is retried.
