APScheduler Tutorial: Running Python Jobs on Interval, Cron, and One-Off Triggers

This tutorial explains how to use APScheduler, a Python library that calls functions on a schedule without relying on system cron or a separate service. It covers three trigger types, interval, cron, and one-off date, and shows how a SQLAlchemy job store in SQLite preserves jobs across restarts. The author notes that job functions must reside in an importable module, since APScheduler stores them by reference and cannot restore functions defined in the main script. The demo builds a scheduler with a metrics-collection job, a weekday summary job, and a self-removing reminder, then verifies that persistent jobs return after a restart. The tests were run with Python 3.12.3 and APScheduler 3.11.3, and the tutorial requires no API keys or external services.