MCP gateway
A single MCP server that fronts many backend APIs, so an agent connects once and can discover, price, and call any of them as tools instead of wiring up a separate server for each provider.
An MCP gateway is an MCP server that stands in front of many underlying APIs and presents them to an agent through one connection. Rather than running a separate MCP server for every provider and managing a key and a billing relationship for each, the agent connects to the gateway and gains a small, uniform set of tools that reach the whole catalogue. The gateway handles the fan-out to backends, the credentials, and the metering behind that single interface.
This differs from a single-purpose MCP server, which exposes one tool or data source. A gateway is the aggregating pattern: discovery is itself a tool, so the agent searches for the capability it needs at run time instead of having every backend wired in advance. The value is that adding the next API becomes a search rather than an integration, and the agent's tool surface stays small no matter how large the catalogue grows.
Proxygate runs as an MCP gateway for buying API access. It exposes tools such as browse_apis, describe_endpoint, get_pricing, check_balance, call_api, get_usage, and rate_seller over Streamable HTTP. An agent connects once, searches the catalogue, inspects an endpoint, and makes a paid call that returns the upstream body, the exact amount charged, and a signed receipt, all from one prepaid USDC balance. Each provider key is injected server-side, so the agent reaches thousands of APIs without ever holding a credential.
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Related concepts
MCP gateway: frequently asked questions
An MCP gateway is a single MCP server that fronts many backend APIs, so an agent connects once and can discover, price, and call any of them as tools, instead of running a separate MCP server and managing a key for each provider.
A single-purpose MCP server exposes one tool or data source. An MCP gateway aggregates many backends behind one connection and makes discovery itself a tool, so the agent searches for a capability at run time rather than wiring every backend in advance.
Yes. Proxygate runs as a remote MCP gateway over Streamable HTTP. One connection gives an agent tools to search the catalogue, inspect endpoints, check a balance, and make paid calls from a single prepaid USDC balance, with each provider key injected server-side.