How I built a monitoring system for my custom domain's email with Python, FastAPI, Google Pub/Sub, and Prometheus.

(From July 2025) Implementing a zero-downtime DNS & email forwarding migration after discovering my previous provider's DNSSEC implementation was essentially broken.

(From March 2023) How I fully configured email authentication for sending (DMARC, DKIM, SPF) and receiving (TLSRPT, MTA-STS) for my vanity domain for reliable deliverability.