# Socket.IO Client

> Publish and subscribe to Socket.IO events.

Socket.IO Client is a client for connecting to Socket.IO servers and inspecting bidirectional event messages.

Also: online socket.io client, socket.io playground, socket.io tester, socket.io client online, postman socket.io client.

## What it does

Enter a Socket.IO endpoint, configure query parameters, headers, events, and connection settings, then send event arguments through Postman.

## When to use it

- You want to test a public Socket.IO endpoint.
- You need to inspect sent and received Socket.IO event arguments.
- You want to troubleshoot a failed Socket.IO handshake/request.

## What you give it

| Input | Meaning |
| --- | --- |
| Socket.IO endpoint | The publicly accessible Socket.IO server URL to connect to. |
| Message | One or more text, JSON, Base64, or hexadecimal arguments. |
| Events | Socket.IO event names to listen for after connecting. |
| Connection configuration | Query parameters, custom headers, and socket settings. |

## What you get back

| Output | Meaning |
| --- | --- |
| Message stream | A searchable timeline of sent, received, connection, and error events. |
| Handshake diagnostics | Connection errors and available Socket.IO handshake details. |

## Key terms

- **Socket.IO** — a persistent event transport where each message can carry multiple arguments.
- **Cloud Agent** — Postman infrastructure that executes connections for you.

## Questions

### Can the playground send binary messages?

Yes. Binary arguments can be composed as Base64 or hexadecimal.

### Can I filter Socket.IO messages?

Yes. Search all visible events or filter the stream to sent or received messages.

### Does the playground use variables?

No. It does not load workspace, collection, environment, cookie, history, or variable state.


## Privacy

Endpoint, headers, settings, and messages 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/socketio-client) — the interactive version of this page.
- [Postman Tools](https://www.postman.com/tools) — every free tool in this set.
- [Guide to Socket.IO requests](https://learning.postman.com/docs/use/send-requests/protocols/websocket/create-a-socketio-request) — Postman documentation.