# Omnisend
### Connection
When you're setting up your first workflow with Omnisend, you'll need to add your **API key** so that Omnisend is a connected app within MESA.
To get an API key:
1\. [Login into your Omnisend account.](https://app.omnisend.com/login)
2\. Once logged in, head over to Omnisend's App Market to connect MESA and Omnisend by clicking on this link in a new tab:
3\. Click on the Connect now button.
4\. On the next screen, click on the Copy API Key button.
5\. Go back into your MESA workflow that contains an Omnisend step. Paste the copied values into the Omnisend API Key field.
6\. After pasting, click on the Add Connection button.
7\. Now go back to the tab with the MESA page in the Omnisend App Market. Click on the checkbox next to I have completed all the steps and on the Confirm button.
### Configure
When using the Omnisend Update/Create Contact [actions](https://docs.getmesa.com/workflow-builder/actions), there is a section for Custom Properties.
1. Select More options, scroll down to the Custom Properties, then click both the Key and Value checkboxes.
2. You can click on Add to add more custom properties that will be added to the Contact in question. Also, you can utilize [MESA's Variables feature](https://docs.getmesa.com/workflow-builder/fields/variables) to send custom data from other integrations.
{% hint style="info" %}
**🗒 Note**: The **Key** can be named anything as you'd like, but cannot include spaces. As a good rule, you should make the **Key** specific to the data sent to Omnisend.
{% endhint %}
### I don't see my Omnisend workflow activating when I update something in Omnisend?
MESA workflows that contain Omnisend [triggers](https://docs.getmesa.com/workflow-builder/triggers) (such as Order Created) will run on a polling system. Meaning, on every hour or whatever the selected frequency is selected in your MESA workflow, MESA will look for any recent activity in Omnisend. As a result, you may not see immediate activity in your MESA workflow until the frequency hits.
In Onmisend triggers, you can find the polling system within More options. You can keep the default frequency or adjust it.
Once the frequency hits, MESA will process every single task that has accrued within the previous timeframe.
{% hint style="info" %}
**🗒 Note**: Please note that available frequencies will differ depending on your MESA billing plan.
{% endhint %}
