What can you build with an AI API?

You can add chat assistants, text summarization, translation, semantic search with embeddings, image generation, speech-to-text, and code completion. Because the model runs remotely, you call it with a few lines of code instead of training or hosting anything yourself.

What's the difference between a single-provider AI API and a model gateway?

A single-provider API like OpenAI or Anthropic gives you that company's models directly and gets new features first. A gateway or aggregator exposes many providers through one key and one schema, so you can switch models or add fallbacks without rewriting your integration.

Do AI APIs use my data to train their models?

It depends on the provider and plan — many now exclude API traffic from training by default, but consumer tiers and some free plans may not. Check each provider's data-retention and training policy, and prefer zero-retention or enterprise terms for sensitive data.

Best AI API Tools (2026)

Compare AI APIs and model gateways for adding LLMs, image generation, speech, and embeddings to your app — from single-provider endpoints to unified multi-model platforms.

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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

App developers

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

Teams comparing models

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

Cost and reliability optimizers

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

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.