Temporary email services (disposable email) are often seen as simple "10-minute mail" scripts. However, building one that is reliable, secure, and doesn't rely on third-party SMTP proxies (like Mailgun or SES) is a great engineering challenge. In this post, I'll walk you through the architecture of DarkEmail , an open-source project I've been maintaining for a year. The Problem with Proxy-based Temp Mails Most temporary email services you find today are just frontends for commercial SMTP providers. They use APIs from Mailgun, AWS SES, or SendGrid to receive mail. While easy to set up, this has three major drawbacks: Privacy Leak : A third-party provider sees every email body passing through. Lack of Control : You can't control the real retention or the raw SMTP headers. Fragility : Commercial providers often block "disposable email" use cases. If they flag your account, your service dies instantly. I wanted a service where I controlled the entire pipeline —from the MX record to the Redis storage.…