What is AI gateway?

What an AI gateway is

An AI gateway is a middle layer. Instead of your app talking directly to OpenAI, Anthropic, Google and others, each with its own account, interface and bill, it talks to one gateway. The gateway forwards each request to the right model and sends the answer back.

Think of a travel agent. You ask for a trip once, and the agent deals with every airline.

What it does

Most gateways offer some mix of these:

• One interface. Many gateways accept requests in a single common format, so switching from one model to another can mean changing a model name rather than rewriting code.
• Routing. Send simple jobs to a cheap, fast model and hard ones to a stronger one, based on rules you set.
• Fallbacks. If a provider is down or slow, the gateway retries the request on another model.
• Cost tracking. Spend, token counts and latency are logged in one place, per team, project or model.
• Limits and controls. Rate limits, budgets and access rules apply in one spot instead of in every app.
• Logging. A central record of requests and responses helps with debugging and auditing.

Vendors differ on which of these they offer and on how they are priced, so check the specifics for the one you use.

Why it matters

Models change fast. A gateway lets a team mix providers and move between them without rebuilding their product, which is how some teams run bulk work on cheaper open-weight models while keeping frontier models for hard problems.

It also concentrates risk. A gateway handles your traffic and often holds your API keys, so it deserves the same care as any system holding credentials. It adds a hop, which can add a little delay, and your prompts pass through one more party, so read its data-handling terms.

Gateway versus other terms

A gateway is not a model. It does not answer questions itself. It also differs from a harness, which wraps a model to run an agent loop. A gateway only moves requests and keeps score. The two are often used together: an agent harness calls models through a gateway.

A simple example

Your app sends a summarization request to the gateway with a preferred model. That provider is rate limited, so the gateway tries a second one. The answer comes back, and the dashboard shows what the request cost. Your code never changed.