> For the complete documentation index, see [llms.txt](https://captic-2.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://captic-2.gitbook.io/docs/overview/hands-on/integrating-your-robot/integration-flow/protocols/udp.md).

# UDP

Send and receive UDP messages.

Use the UDP nodes to send and receive lightweight messages without a connection. You'll find them under **udp** in the palette.

| Node    | What it does                                           |
| ------- | ------------------------------------------------------ |
| udp in  | Listens on a port and outputs each message it receives |
| udp out | Sends a message to a host and port                     |

UDP doesn't guarantee delivery. Use it for frequent status updates where an occasional lost message doesn't matter, and use [TCP](/docs/overview/hands-on/integrating-your-robot/integration-flow/protocols/tcp.md) or a PLC protocol for results that must arrive.

For node details, see the [Node-RED documentation](https://nodered.org/docs/user-guide/nodes).