A small self-hosted email reminder service built with Python and Postfix

A Reddit user described an email reminder service built with Python and Postfix. The user says you can send an email to an address such as 3days@ and receive it back after that time. The setup uses Postfix in Docker, SQLite, a cron job, and a Hetzner SMTP relay. The author says it runs on a €5/month VPS alongside two other services.

Key points

  • The email address itself tells the service when to send the reminder back.
  • The post lists formats such as 30min, 4hours, 2weeks, tuesday, and nextmonth.
  • Postfix receives the mail and passes it to a Python script.
  • The service stores the raw .eml file on disk and writes a row to SQLite.
  • A cron job checks every 10 minutes for reminders that are due.

Quick term guide

Postfix
Software that helps a server receive and send email.
Docker
A tool that packages an app with what it needs to run in many places.
SQLite
A small database that can run inside an app or browser without a separate server.
Mac mini server
A Mac mini used as an always-on computer for files, apps, backups, or automation.
Mac mini
A small desktop computer made by Apple.
server
A computer that stores files and shares them with other devices in your home.
Python script
A Python script is a small program written in the Python language.
script
A small program that automates repeated steps.
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