Blog

An SMTP sandbox captures outgoing emails without delivering them. Here's exactly how it works, when to use one, and how it fits into development, staging, and CI/CD workflows.

Broken links, missing images, wrong recipients, encoding failures, and silent delivery drops. These are the email bugs that ship to production most often, and here is how to catch every one of them.

SMTP is the protocol your application uses to send email. Here's how it works at the protocol level, what happens during a typical SMTP session, and why understanding it makes you better at debugging delivery failures.

Transactional emails need systematic testing across five layers: trigger logic, content, delivery, queues, and rendering. Here's how to build a complete testing workflow.

SPF, DKIM, and DMARC determine whether your emails reach the inbox or land in spam. Here's what each one does, how to set them up, and how to debug failures.

Staging email leaks happen more often than anyone admits. Here's why they keep happening and five layers of defense to make them structurally impossible.

Docker gives you isolated, reproducible SMTP testing. Here's the complete guide to Docker Compose setups, multi-service configs, CI/CD integration, and troubleshooting.

When an email fails to deliver, the answer is in the headers and SMTP response codes. Here's how to read them, trace delivery paths, and debug common problems.

Eight concrete practices for catching email bugs before production: SMTP sandboxes, content assertions, CI integration, edge cases, header verification, and more.

A fake SMTP server captures emails without delivering them. Here's how to set one up with Mailpit, SendPit, or Python — with framework configs for Laravel, Django, Rails, and Node.js.