Learn

Short, opinionated guides for people who'd rather understand it once than copy-paste records on Stack Overflow.

Fundamentals

• What is SPF?
  Sender Policy Framework, explained without the RFC-speak.
• What is DKIM?
  How DomainKeys Identified Mail cryptographically signs messages.
• What is DMARC?
  The standard that finally lets you block spoofed mail.
• What is BIMI?
  Display your logo in inbox lists, like the trusted brands.

Hands-on guides

• DMARC rollout guide
  A week-by-week playbook from p=none to p=reject without breaking mail.
• The SPF 10-lookup limit
  Why hitting it breaks delivery, and how each major ESP counts against you.
• DKIM selector cheat sheet
  Which selector each ESP uses, with curl/dig examples for each.
• Google 2024 sender requirements
  What changed in February 2024 and how to comply if you send over 5,000 messages/day.