# gRPC Client

> Invoke unary and streaming methods on a gRPC server.

gRPC Client is a signed-out gRPC client for loading protobuf methods, composing messages, and invoking gRPC services through Postman's Cloud Agent.

Also: online grpc client, grpc client, protobuf client, grpc server reflection, grpc api testing.

## What it does

Enter a gRPC server URL, import a .proto file or use server reflection, choose a method, send a JSON-formatted protobuf message, and inspect response messages, metadata, and trailers.

## When to use it

- You want to test a gRPC service.
- You need to load service methods from a protobuf file.
- You need to inspect gRPC metadata, trailers, and status codes.

## What you give it

| Input | Meaning |
| --- | --- |
| gRPC server URL | The publicly accessible gRPC server host to invoke. |
| Service definition | A local .proto file or a service definition loaded from server reflection. |
| gRPC message | A JSON representation of the protobuf request message, plus authorization, metadata, and settings. |

## What you get back

| Output | Meaning |
| --- | --- |
| gRPC response | Response messages with gRPC status, timing, metadata, and trailers. |
| Loaded methods | A method selector populated from the imported protobuf descriptor or server reflection. |

## Key terms

- **Protobuf** — the interface definition format gRPC uses to describe services and messages.
- **Server reflection** — a gRPC service feature that lets clients discover available methods at runtime.
- **Cloud Agent** — Postman infrastructure that executes requests for you.

## Questions

### Why can I not reach my localhost?

This tool cannot access localhost, or any endpoint behind your firewall or VPN, because it runs on the internet rather than on your computer. To reach one, sign in to Postman and use either the Postman Desktop App or the Desktop Agent in the web app. Both run on your own machine: the request goes straight from your computer to your endpoint, and your request data and credentials never pass through Postman's cloud.

### Can the playground use server reflection?

Yes. Enter a server URL, open Service definition, and choose Use Server Reflection.

### Can I import protobuf files?

Yes. Import a local .proto file from the Service definition tab.

### Does the playground load Postman workspaces or variables?

No. It does not load workspace, collection, environment, history, variable, Spec Hub, or account state.


## Privacy

Server URL, message, metadata, settings, and authorization data are sent to Postman Cloud Agent for execution. The playground does not load workspace or account data.

## Links

- [Use the tool](https://www.postman.com/tools/grpc-client) — the interactive version of this page.
- [Postman Tools](https://www.postman.com/tools) — every free tool in this set.
- [Guide to gRPC requests](https://learning.postman.com/docs/sending-requests/grpc/grpc-request-interface/) — Postman documentation.