Signal Start Event by REST API with businessKey

I’m using Camunda Run 7.18 and the API REST.
After searching for many days, I still can’t find the way to send the BusinessKey with a Signal Start Event and a POST request.
Below the extract of my bpmn file based on documentation at Signal Events |

Whatever I’ve tried, the process start but the businessKey is not set. I can only see the variable.

   <bpmn:startEvent id="StartEvent_1">
      <bpmn:signalEventDefinition id="SignalEventDefinition_0zgilgu" signalRef="Signal_2kqubni">
          <camunda:in businessKey="${execution.processBusinessKey}" /> (or =${variableName} or ="555")

and my post to {{baseUrl}}/signal

    "name": "SIGNAL_NEW",
    "variables": {
        "processBusinessKey": {

Someone has been successful?

Hi @Ivano,

The link you are referring to is about passing business key from a throwing signal.

You can try below solution for your case

Thank you @hassang

We are planning to use Camunda Run in our microservices saas as out-of-the-box service, managed only by REST API and therefore Java Delegate is not an option available.

We thought to Signal to start processes because of the 1 to 1 message-process behaviour.

Hi @Ivano,

You can write the execution listener using any supported scripting language.

Attached is a simple running example
test_signal_process.bpmn (2.7 KB)

If 1 to 1 message-process behavior is the target, why not use start message event instead of using start signal event

Awesome @hassang,
you save my day, many thanks.

PS: we have more processes that starts with the same “back end event” ad so translate to Message Start Event is not possible. So 1:1 is the undesidered behaviour.

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