API gateway
A server that sits in front of one or more backend APIs and handles cross-cutting concerns, such as routing, authentication, rate limiting, and metering, in one place instead of in every backend.
An API gateway is a single entry point placed in front of one or more backend services. Instead of every client talking directly to every backend, and every backend separately implementing authentication, rate limiting, and logging, the gateway handles those concerns once, then routes each request to the right backend. This matters most where there are many backends (a microservices architecture) or many external callers (a public API), because it keeps the cross-cutting logic in one place rather than duplicated everywhere.
A typical API gateway authenticates the caller, enforces rate limits or quotas, routes the request to the correct backend based on path or method, and often meters usage for billing. What it usually does not do is change the meaning of the request or response, it adds control and visibility around the call, not a different call.
Proxygate runs an API gateway purpose-built for agent buyers rather than internal microservices. One connection, over MCP, an SDK, a CLI, or REST, gives an agent routing to any listed provider, with authentication (the agent's Proxygate identity), metering (pay-per-call against a prepaid USDC balance), and key injection (the provider's credential added server-side) all handled at the gateway rather than by the agent or the provider.
Related concepts
API gateway: frequently asked questions
An API gateway is a single entry point in front of one or more backend APIs that handles routing, authentication, rate limiting, and metering in one place, so those concerns do not have to be built into every backend separately.
An API gateway is a specific kind of proxy focused on routing requests to the right backend while handling authentication, rate limiting, and metering. A proxy is the broader category: any intermediary that forwards traffic on a client's behalf, with or without those extra concerns.
Yes, purpose-built for agent buyers. One connection gives an agent routing to any listed provider, with the agent's Proxygate identity for auth, pay-per-call metering against a prepaid USDC balance, and server-side key injection, reachable over MCP, an SDK, a CLI, or REST.