I want to update tickets using a trigger or automation. The ticket attributes I want to update are not accessible using business rules. I can make the update successfully using the Support API. Can I have the trigger or automation notify a webhook that updates the ticket through the API?
No, this workflow is not recommended or supported. When a ticket is updated by business rules and the API simultaneously, errors are likely to occur. When this happens, it is called a race condition.
Every time a ticket is created or updated, all your business rules run in a cycle against that ticket. For instance, triggers fire and update the ticket if their conditions are met during the cycle. A cycle is the entire process of a ticket being checked against all your triggers.
When a trigger updates a ticket using the API, the update occurs at some indeterminate point in the cycle. Results can vary based on when the ticket update occurs in the cycle. The ticket update can affect whether other business rules fire.
For more information, see the article: About triggers and how they work.