API access lets one software service communicate with another through a defined interface. The provider can limit which data the service may read or which actions it may perform, often using scoped tokens rather than a customer’s full login credentials.
In cyber security, narrow permissions can reduce the damage if a third-party service is compromised and make access easier to monitor or revoke. For example, a banking API might permit an approved service to retrieve account balances without allowing transfers. APIs still require careful controls: providers should authenticate callers, restrict permissions, log activity, protect tokens, and let users withdraw access.