head to head · open source
apscheduler vs ical4j
apscheduler has 7,630 GitHub stars, 784 forks, 53 open issues and last shipped 8 days ago. ical4j has 837 stars, 218 forks, 162 open issues and last shipped 29 days ago. apscheduler leads on adoption by 812% (7,630 vs 837 stars). apscheduler is written in Python under MIT; ical4j is written in Java under BSD-3-Clause. apscheduler has attracted 10% as many forks as stars, ical4j 26%. apscheduler was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (scheduling), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| apscheduler | ical4j | |
|---|---|---|
| GitHub stars | ★ 7.6K | ★ 837 |
| License | MIT | BSD-3-Clause |
| Written in | Python | Java |
| Last push | 2026-09-10 | 2026-08-20 |
| Forks | ⑂ 784 | ⑂ 218 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick apscheduler if
- You weight community size — 7.6K stars and counting
- You want the MIT license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick ical4j if
- You want the ical4j feature set and don't need the biggest community
- You prefer the BSD-3-Clause license terms
- Your stack matches Java
- You evaluated both and ical4j fits your workflow better
About apscheduler
APScheduler is an MIT licensed Python library that provides task scheduling and job queuing, scaling from a single process script to multi node deployments that share a persistent data store.
read the full apscheduler overview →
About ical4j
iCal4j is a BSD 3 Clause licensed Java library that reads and writes iCalendar data streams and exposes them as an object model, built for Java developers who need to handle calendar data such as events, appointments and to do lists inside their own applications.
read the full ical4j overview →
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Frequently asked questions
Is apscheduler or ical4j more popular?
apscheduler has 7,630 GitHub stars and ical4j has 837. apscheduler has the larger community by that measure.
Are apscheduler and ical4j free?
Both are open source. apscheduler is licensed under MIT and ical4j under BSD-3-Clause. Neither carries a licence fee.
What is the difference between apscheduler and ical4j?
apscheduler is written in Python and ical4j in Java. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, apscheduler or ical4j?
Choose apscheduler if you want the larger community (7,630 stars) or its MIT licence terms. Choose ical4j if its feature set, stack or BSD-3-Clause licence fits better. Both are self-hostable.