Currently, we don't have a direct way to add a template-based API call to a waterfall step. However, we're working on expanding our custom waterfall capabilities.
For now, you can create a custom waterfall by following these steps:
1. Click "+Add Column > β΄Waterfall"
2. Select a column data type (text, number, URL)
3. Click "Add Action"
4. Select any integration to use depending on your use case
5. Adjust the order of integrations as needed
We're continuously improving our platform. Is there a specific API or integration you're looking to include in your waterfall?