Hi, Josula!

In terms of the API, there is no way to automatically do this. It would require parsing a message body using logic of your own to extract. 

However, within Front there may be an easier way to accomplish what you are looking for. If you have access to custom rules and dynamic variables, you could construct your own rule to trigger at your discretion and extract email addresses from a message. This would also require some logic on your end to determine what is extracted in the dynamic variable, but it could accelerate the process. 

After setting your rule conditions and logic of how you want to extract the email from the signature, you could then take an action of your choosing, including sending the dynamic variable info to a webhook. 

Hopefully this helps provide some additional insight into how a solution could be reached for your workflow. 

Best, 
Justin

You can also submit an idea to have signatures parsed and returned separately by the API for easier processing