An API, which stands for application programming interface, is how systems talk to one another.

APIs safely expose the internal logic of an application so other systems can build off it “on their own property”. Other applications can use these functions and tools without accessing another application’s codebase.

Because a service controls the logic it exposes externally in an API, systems that use it are limited by what logic the API exposes and how it’s exposed.

Some platforms, such as Plaid and Opal, utilize API integrations heavily. This allows these platforms to consolidate authorization across systems.