# Conditional StartEvent

**URL:** <https://forum.flowable.org/t/conditional-startevent/11934>\
**Category:** Flowable Engine\
**Created:** [December 12, 2024, 8:07am UTC](https://forum.flowable.org/t/conditional-startevent/11934 "2024-12-12T08:07:13Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![thmarx](https://avatars.discourse-cdn.com/v4/letter/t/87869e/32.png) [@thmarx](https://forum.flowable.org/u/thmarx)\
**Post date:** [December 12, 2024, 8:07am UTC](https://forum.flowable.org/t/conditional-startevent/11934/1 "2024-12-12T08:07:13Z")

</div>

Hello,

We are using flowable os in an embedded setup. And we are trying to evaluate some properties before starting the process.

We found other engines supporting things like conditional start event and we wonder if this is also possible with flowable.

```auto
<startEvent id="conditionalStartEvent">
  <conditionalEventDefinition camunda:variableName="temperature">
    <condition type="tFormalExpression">${temperature > 20}</condition>
  </conditionalEventDefinition>
</startEvent>

```

If these evaluations are not possible, we need to do these checks before trying to start the process. What is also a valid solution for us.

Kind regards

---

<div class="post-metadata">

**Author:** ![filiphr](https://yyz1.discourse-cdn.com/flex035/user_avatar/forum.flowable.org/filiphr/32/315_2.png) [@filiphr](https://forum.flowable.org/u/filiphr)\
**Post date:** [December 12, 2024, 8:59am UTC](https://forum.flowable.org/t/conditional-startevent/11934/2 "2024-12-12T08:59:07Z")

</div>

Hey @thmarx,

On the engine level, Flowable does support conditional event. However, not as a start event of a regular process. It is supported for an Event Sub Process Start Event, Intermediate Catch Event and Boundary Event.

> [@thmarx](#):
>
> We found other engines supporting things like conditional start event

Are you sure that other engines support it on the top process level, and not an Event Sub Process?

In any case, Flowable has CMMN, which together with BPMN might be a better fit for what you need.

You can read [Start Conditional Event not able to trigger - #2 by filiphr](https://forum.flowable.org/t/start-conditional-event-not-able-to-trigger/6356/2), which is related to what you are asking for.

With CMMN you can solve this by using a Process Task that has a Sentry with the expression `${temperature > 0}`

Cheers,  
Filip

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<div class="post-metadata">

**Author:** ![thmarx](https://avatars.discourse-cdn.com/v4/letter/t/87869e/32.png) [@thmarx](https://forum.flowable.org/u/thmarx)\
**Post date:** [December 12, 2024, 12:51pm UTC](https://forum.flowable.org/t/conditional-startevent/11934/3 "2024-12-12T12:51:48Z")

</div>

Hey,

the camunda documentation has two separat sections for ConditionlStartEvents and CondionalStartEvents for sub processes. Though we thought that’s the case.

I will have a look at the information you provded.

Thank you.