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API (application programming interface)

Using AI Last reviewed 2026-06-11

Definition A defined way for software programs to communicate with each other. AI providers expose their models through APIs, letting firms and vendors build the models into their own tools and workflows.

In more depth

Instead of a person typing into a chatbot, a program sends a request—prompt, documents, settings—to the provider's API and receives the model's output for use inside an application. Most legal AI products are built this way on top of a few major model providers. API terms often differ from consumer-app terms, commonly including no training on customer inputs and shorter retention, which matters when tracing where client data actually flows.

Further reading: Wikipedia.

Related terms

Closed modelEnterprise AIInferenceZero data retention (ZDR)

About the editor: MHSB Solutions, Research desk. MHSB Solutions is not a law firm. This glossary is educational information, not legal advice.

Educational information, not legal advice. AI terminology and tools change quickly; definitions reflect usage as of the last-updated date. For what bar associations and courts actually require of lawyers using AI, see legalaicompliance.help and consult a licensed attorney in your jurisdiction.