About howto.email

howto.email is a free, open-source, vendor-neutral knowledge base and troubleshooting toolbox for email infrastructure. It is built to be useful whether you are learning how email works, administering a production environment, or trying to understand why a particular configuration behaves the way it does.

Coverage includes SMTP, DNS, SPF, DKIM, DMARC, TLS, deliverability, mailbox protocols, security, troubleshooting, Microsoft 365, Google Workspace, application sending, incident response, and modern email operations.

Documentation and tools

The site is organized around a simple workflow: learn the concept, look up the technical details, inspect the environment, understand the result, make an appropriate change, and test again.

Interactive tools such as Domain Check complement the documentation. They inspect public information and connect findings to relevant howto.email articles. The tools are not intended to replace the documentation with a single score or a black-box recommendation.

Vendor neutral by design

Email crosses products, providers, networks, and standards. howto.email therefore focuses on protocols and observable behavior first. Vendor-specific documentation is included where implementation details matter, but references to a company, service, or product do not imply endorsement.

Open and practical

The project favors primary standards, authoritative documentation, reproducible troubleshooting steps, and explanations that show the evidence behind a finding. Tools are designed to work without requiring an account or turning the site into a hosted email-management platform.