Technical
API (Application Programming Interface)
A set of protocols and tools that allow software applications to communicate with AI services programmatically, enabling integration of AI capabilities into products.
Explained at five levels
Level 1
A special door that lets different computer programs talk to each other and share information.
Level 2
A way for apps and websites to connect to AI services — like how a weather app gets data from a weather service. Developers use APIs to build things with AI.
Level 3
A set of protocols and tools that allow software applications to communicate with AI services programmatically, enabling integration of AI capabilities into products.
Level 4
A structured interface exposing AI model capabilities to external applications via HTTP endpoints, typically offering text completion, embeddings, and function calling with authentication, rate limiting, and usage-based pricing.
Level 5
A RESTful or gRPC service layer abstracting model inference behind versioned endpoints — supporting streaming completions, tool-use schemas, structured output grammars, and batched async processing with SLA guarantees.
Definitions are educational summaries. Terminology can vary by source and context.
Sources
- NIST Trustworthy and Responsible AI Resource Center: Glossary — National Institute of Standards and Technology. Accessed 2026-07-20.