# Peer
> Peer object allows easily interacting with connected clients.
When a new client connects to the server, crossws creates a peer instance that allows getting information from clients and sending messages to them.
## Instance properties
### `peer.id`
Unique random identifier ([uuid v4](https://developer.mozilla.org/en-US/docs/Glossary/UUID)) for the peer.
### `peer.request?`
Access to the upgrade request info. You can use it to do authentication and access users headers and cookies.
This property is compatible with web [Request](https://developer.mozilla.org/en-US/docs/Web/API/Request) interface, However interface is emulated for Node.js and sometimes unavailable. Refer to the [compatibility table](#compatibility) for more info.
### `peer.remoteAddress?`
The IP address of the client.
Not all adapters provide this. Refer to the [compatibility table](#compatibility) for more info.
### `peer.websocket`
Direct access to the [`WebSocket`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket) instance.
WebSocket properties vary across runtimes. When accessing `peer.websocket`, a lightweight proxy increases stability. Refer to the [compatibility table](#compatibility) for more info.
### `peer.context`
The context is an object that contains arbitrary information about the request.
You can augment the `PeerContext` interface types to add your properties.
```ts
declare module "crossws" {
interface PeerContext {
customData?: string[];
}
}
```
context data can be volatile in some runtimes.
### `peer.topics`
All topics, this peer has been subscribed to.
### `peer.namespace`
Peer's pubsub namespace.
## Instance methods
### `peer.send(message, { compress? })`
Send a message to the connected client.
### `peer.subscribe(channel)`
Join a broadcast channel.
### `peer.unsubscribe(channel)`
Leave a broadcast channel.
### `peer.publish(channel, message)`
Broadcast a message to the channel. The peer that the publish is called on itself is excluded from the broadcast.
### `peer.close(code?, number?)`
Gracefully closes the connection.
Here is a list of close codes:
- `1000` means "normal closure" (default)
- `1009` means a message was too big and was rejected
- `1011` means the server encountered an error
- `1012` means the server is restarting
- `1013` means the server is too busy or the client is rate-limited
- `4000` through `4999` are reserved for applications (you can use it!)
To close the connection abruptly, use `peer.terminate()`.
### `peer.terminate()`
Abruptly close the connection.
To gracefully close the connection, use `peer.close()`.
## Compatibility
|
|
Bun
|
Cloudflare
|
Cloudflare (durable)
|
Deno
|
Node (ws)
|
Node (μWebSockets)
|
SSE
|
send()
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
publish()
/
subscribe()
|
✓
|
⨉
|
✓
1
|
✓
1
|
✓
1
|
✓
|
✓
1
|
close()
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
terminate()
|
✓
|
✓
2
|
✓
|
✓
|
✓
|
✓
|
✓
2
|
request
|
✓
|
✓
|
✓
3
|
✓
|
✓
4
|
✓
4
|
✓
|
remoteAddress
|
✓
|
⨉
|
⨉
|
✓
|
✓
|
✓
|
⨉
|
websocket.url
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
|
websocket.extensions
|
✓
5
|
⨉
|
⨉
|
✓
5
|
✓
5
|
✓
5
|
⨉
|
websocket.protocol
|
✓
6
|
✓
6
|
✓
6
|
6
✓
|
✓
6
|
✓
6
|
⨉
|
websocket.readyState
|
✓
|
✓
|
✓
|
✓
|
✓
|
✓
7
|
✓
7
|
websocket.binaryType
|
✓
8
|
⨉
|
⨉
|
✓
|
✓
8
|
✓
|
⨉
|
websocket.bufferedAmount
|
⨉
|
⨉
|
⨉
|
✓
|
✓
|
✓
|
⨉
|
## Footnotes
1. pubsub is not natively handled by runtime. peers are internally tracked. [↩](#user-content-fnref-1) [↩
2
](#user-content-fnref-1-2) [↩
3
](#user-content-fnref-1-3) [↩
4
](#user-content-fnref-1-4)
2. `close()` will be used for compatibility. [↩](#user-content-fnref-2) [↩
2
](#user-content-fnref-2-2)
3. After durable object's hibernation, only `request.url` (and `peer.id`) remain available due to 2048 byte in-memory state limit. [↩](#user-content-fnref-30)
4. using a proxy for [Request](https://developer.mozilla.org/en-US/docs/Web/API/Request) compatible interface (`url`, `headers` only) wrapping Node.js requests. [↩](#user-content-fnref-31) [↩
2
](#user-content-fnref-31-2)
5. [`websocket.extensions`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/extensions) is polyfilled using [`sec-websocket-extensions`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Protocol_upgrade_mechanism#websocket-specific_headers) request header. [↩](#user-content-fnref-4) [↩
2
](#user-content-fnref-4-2) [↩
3
](#user-content-fnref-4-3) [↩
4
](#user-content-fnref-4-4)
6. [`websocket.protocol`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/protocol) is polyfilled using [`sec-websocket-protocol`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Protocol_upgrade_mechanism#websocket-specific_headers) request header. [↩](#user-content-fnref-5) [↩
2
](#user-content-fnref-5-2) [↩
3
](#user-content-fnref-5-3) [↩
4
](#user-content-fnref-5-4) [↩
5
](#user-content-fnref-5-5) [↩
6
](#user-content-fnref-5-6)
7. [`websocket.readyState`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/readyState) is polyfilled by tracking open/close events. [↩](#user-content-fnref-6) [↩
2
](#user-content-fnref-6-2)
8. Some runtimes have non standard values including `"nodebuffer"` and `"uint8array"`. crossws auto converts them for [`message.data`](/guide/message#messagedata). [↩](#user-content-fnref-7) [↩
2
](#user-content-fnref-7-2)