# 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.

## Tools

- [REST API Client](https://www.postman.com/tools/rest-api-client): REST API Client is a signed-out HTTP client for building and sending requests.
- [GraphQL Client](https://www.postman.com/tools/graphql-client): GraphQL Client is a signed-out GraphQL client with schema introspection and a visual query builder.
- [gRPC Client](https://www.postman.com/tools/grpc-client): gRPC Client is a signed-out gRPC client for loading protobuf methods, composing messages, and invoking gRPC services through Postman's Cloud Agent.
- [MCP Client](https://www.postman.com/tools/mcp-client): MCP Client is a signed-out MCP workbench for connecting to remote HTTP MCP servers and inspecting their capabilities.
- [WebSocket Client](https://www.postman.com/tools/websocket-client): WebSocket Client is a client for connecting to WebSocket servers and inspecting bidirectional messages.
- [Socket.IO Client](https://www.postman.com/tools/socketio-client): Socket.IO Client is a client for connecting to Socket.IO servers and inspecting bidirectional event messages.
- [Webhook sender](https://www.postman.com/tools/webhook-sender): The webhook sender fires a realistic Stripe, GitHub, Shopify, Slack, Twilio or custom webhook event at an endpoint you own, signs it with your own secret so it passes real signature verification, and shows you the response your handler returned.

## About

- No account is required and there is nothing to install. Each tool's Privacy section explains what stays in your browser and what is sent to Postman.
- [Postman Tools](https://www.postman.com/tools) — every tool, not just this group.
- [llms.txt](https://www.postman.com/tools/llms.txt) — the same index in llms.txt form.