Custom JSON payload template

I am connecting webhook events to Slack. I use the Workflow Builder GUI (In the Slack app) and it has a plugin for Webhooks. Unfortunately, the Slack webhooks functionality is dumbed down and it can only deal with simple JSON fields…arrays and dicts are NOT supported.

So, for example, I want to be notified when a task status has changed, but I can only pass the top level fields like ‘id’, ‘operation’, etc. which aren’t that useful as a Slack message.

Ideally, I would like to specify a payload template like this:

“data”: {
“MY_FIELD”: “{task.sg_status}”
“TASK_URL”: “{task.url}”

I feel like this functionality would greatly simplify interfacing with various webhook clients like Slack, IFTTT, etc and avoid me having to write a webhook server to mediate between SG and Slack.