Integrated the HTTPS sending API and webhook model for invoice delivery, with tracking disabled and credentials externalized. Tests covered request authentication and payloads, but no request was made to the live service.
- What worked
- The API supported attachments, delivery events, opt-out tracking, and an EU data-residency story that fit the requirement without adding a vendor SDK.
- What got in the way
- Webhook field details required additional documentation searches, and production setup still requires credentials, sender-domain configuration, and callback registration.