What is an AI gateway?
One API in front of many model providers: what it does, and when it is worth it.
The problem it solves
Using more than one AI provider directly means one account, key, SDK quirk, bill and outage page per provider. Switching a feature from one model to another becomes a code change. A gateway collapses that: one endpoint, one key, one balance, and the model is just a string in the request.
What a gateway does
One request shape. Most gateways speak the OpenAI API, so any OpenAI SDK or compatible tool works by changing the base URL. The gateway translates for providers with a different format.
Failover. When a model is served by more than one provider, a failed request moves to the next route instead of returning an error. On Rapid Router the response names the provider that served it (failover and routing).
Billing and limits. One prepaid balance across every model, per-key spending caps, budgets and usage export, instead of a separate invoice from each provider.
Visibility. One log of every request with its model, provider, tokens and cost.
When it is worth it
A gateway pays off when you use two or more providers, want to try new models without new accounts, need failover, or want one invoice. If you use a single provider, have a dollar card and never plan to switch, calling it directly is simpler.
What to look for
The price model (a fee on top-ups, a per-request markup or a subscription), the size of the catalogue, whether it passes prompt caching through at the provider's cache rate, how failover is reported, data handling, and the currency you are billed in. Our comparison of nine gateways lays these out side by side.
How Rapid Router works
Rapid Router is a hosted gateway: one OpenAI-compatible API at https://rapidrouter.ai/api/v1 in front of Claude, GPT, Gemini and 600+ other models. Requests are billed at the provider's list price per million tokens, with a platform fee charged once when you buy credits. The quickstart gets a first request working in a couple of minutes.
Common questions
What is an AI gateway?
A single API that sits between your code and many AI model providers. You send every request to one endpoint with one key, and the gateway forwards it to the right provider, handles failures and keeps one bill.
Is an AI gateway the same as an LLM router?
Close. A router is the part that decides where a request goes; a gateway adds the rest: authentication, billing, budgets, logging and failover.
Does a gateway add latency?
One network hop. The routing itself is a lookup and a forward, so the provider's own speed dominates response time. Streaming and a reused connection matter far more.
Should I self-host a gateway?
Self-hosted proxies such as LiteLLM give you full control and need your own provider accounts, keys and upkeep. A hosted gateway trades that control for one account and one invoice. Teams with strict data rules often self-host; small teams usually do not.