What is an AI API?

An AI API is an HTTP endpoint you send a request to — a prompt, image, or audio — and get back a model's output, so you can add AI features without training or hosting models yourself. You authenticate with an API key and pay per token or per request. Some are single-provider (OpenAI, Anthropic, Google); others are gateways that route one request across many models.

What AI APIs offer

  • REST and streaming endpoints for chat, image, and audio
  • One API key routing across many model providers
  • Token-based, pay-as-you-go pricing with usage dashboards
  • Official SDKs for Python, JavaScript, and more
  • Function calling, structured output, and tool use
  • Rate limits, fallbacks, and OpenAI-compatible schemas

Who uses AI APIs

01

App developers

Add chat, summarization, or vision to a product without running your own model infrastructure.

02

Teams comparing models

Test GPT, Claude, Gemini, and open models behind one gateway to pick the best fit per task.

03

Cost and reliability optimizers

Route requests to cheaper or faster models and fail over automatically when a provider goes down.

04

Agent and automation builders

Wire function calling and tool use into agents, workflows, and backend jobs.

How AI APIs work

Your app sends an HTTPS request with an API key and a JSON payload — the prompt plus parameters like model and temperature — to the provider's endpoint. The model runs inference on their servers and returns the result, either all at once or streamed token by token. Gateways sit in front of several providers, translating one request format (often OpenAI-compatible) to whichever model you target and metering usage for billing.

AI API FAQs