User Datagram Protocol (UDP). With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol (IP) network.

In this document you will learn the basics of how to connect your networked devices to thethings.iO with UDP.


Before you start learning how to use our platform to connect your devices, we recommend that you read first our Getting Started guide in order to create your Account and set up the platform.

Getting Started

In order to send messages from your devices to thethings.iO using the protocol UDP, first you have to create a UDP device group, as you can see in the image below.


Here you can find a guide of how to connect and construct the messages. You can also find examples in different programming languages in our GitHub repository.

Connection parameters

Format is HEX String.
UDP thethings.iO gateway IP:
The port is: 28399

This is the structure of the message:


Note that each byte is represented by two characters (e.g number 1 (dec) is 0x01 (padded hex)). Then, the whole string must be an even number.

thethings.iO header

To be able to communicate with our UDP service, you first have to add a header to your UDP data. At this moment we provide two possible headers to best adapt to your use case.

Using your own deviceId.

You don't have to activate the things. They will be activated automatically once you send first message

Byte 00x00Header type: deviceId
Byte 1Number (hex)
Ex: Device Profile Id = 32609 means 0x7F 0x61 so the value here is 0x02 (2 bytes) that is the length
Length of the Id device group value
Bytes 2 to 2+(deviceGroupId length)Number (hex)
Ex: Device Profile Id = 32797 means 0x7F 0x61 so the value here is 0x7F 0x61
deviceGroupId Value.
Bytes 2+(deviceGroupId length) to 16+(deviceGroupId length)String
Ex: device profile hash is ABCDEFGHIJKLMN the value here is "ABCDEFGHIJKLMN" or what is the same: 0x41 0x42 0x43 0x44 0x45 0x46 0x47 0x48 0x49 0x4a 0x4b 0x4c 0x4d 0x4e
deviceGroupId Hash string
Byte 16+(deviceGroupId length)Number (hex)
Ex: Your device id (fixed by you) is ABCD the length is 4 so the value must be: 0x04
deviceId Length
Bytes 17+(deviceGroupId length) to 17+(deviceGroupId length)+(deviceId Length)String
Ex: Your device id (fixed by you) is ABCD the value here is "ABCD" or what is the same: 0x41 0x42 0x43 0x44
DeviceId String
Last Bytes of the Frame Hex Payload to be parsed Message Payload

Using our thingToken

Things must be activated before you send first message.

Byte 00x01Header type: thingToken
Bytes 1 to 43StringthingToken
Last Bytes of the FrameHex Payload to be parsedMessage Payload

Message Payload

Once you have the header you have to concatenate it with the payload. The payload consists on a hex array. The whole hex array must have an even number of bytes. (Payload example after the UDP header: 0x01 0x02)

This payload will be sent as a hex string to a cloud code function which will parse the payload sent by your devices (udp_parser). This cloud code function is created automatically when you create a new UDP device group.


This part of the message is optional. By default isn't enabled, so we have to configure manually to be ready to work. Contact us in case you want to use this feature

You can concatenate an HMAC-SHA1 hash at the end of the message. To generate the hash you have to use your payload and share with us a generated PSK (Pre-Shared Key): HMAC-SHA1(PLAIN_MESSGAGE, PSK)

Cloud Code Function

The last step is to use our Cloud Code service to code a JavaScript function to parse the payload sent by your devices.

You have to edit the function 'udp_parser' that was created automatically once your device group was created.

This function has two parameters, params and callback. The params, contains the deviceId and the payload. And callback, it's used to sent the result of the parse function to our platform and store the values with our JSON formatting.

params = {
  thingToken: thingToken,
  deviceId: deviceId,
  data: hex payload
function main(params, callback){
    var result = [
          "key": "temperature",
          "value": parseInt('0x'+params.data.substring(0,2))
    callback(null, result); 

As a result you have to return an array of objects with this structure:

[ {"key": temperature, "value": 21}, {"key": humidity, "value": 50} ... ]

Status code

When sending messages, you will receive a status code back indicating if the message was received correctly. In case it wasn't, the error code will indicate what is wrong.

In case you don't know how to fix the issue, we kindly ask you to contact us indicating the problem

Status codeMeaningObservations
0x20 OK. Cloud function was called successfully It means that the message is correctly formatted and the function udp_parser was called. However, it doesn't ensures that the result of the function was successful
0x00Internal errorPlease contact us
0x01Invalid protocolYou are using a protocol different from 0x00 or 0x01
0x02Invalid device group IdThe device group doesn't exist.
0x03Invalid device group hash
0x04Thing not found
0x05Message or Key length incorrect
0x06Invalid HMAC-SHA1 hash
0x07Device group is wrong
0x08Organization has no subscription plan
0x09Subscription Plan is expired
0x10Insufficient Activation CodesYou have reached the number of things of your plan. Please get more activation codes
0x11Error when activating a new a thing
0x12Error when setting thing's name
0x13Thing token not found