Online API Clients

An API client sends a request to a server and shows you what comes back, right in your browser — no account and nothing to install. Postman's clients cover REST, GraphQL, gRPC, WebSocket, Socket.IO, MCP, and signed webhook delivery, so pick the protocol you're working with below.

REST API Client

Test REST, SOAP, SSE, and other HTTP-based APIs.

GraphQL Client

Create and run GraphQL queries and mutations.

gRPC Client

Invoke unary and streaming methods on a gRPC server.

MCP Client

Connect to remote MCP servers and inspect their capabilities.

WebSocket Client

Connect to a WebSocket server and send or receive messages.

Socket.IO Client

Publish and subscribe to Socket.IO events.

Webhook sender

Send a signed mock webhook event to your endpoint.