Tasks.org
Open-source To-Do Lists & Reminders
Open source
Tasks is free software, licensed under the GNU GPLv3
Open protocols
Tasks.org is compatible with Outlook, Thunderbird, Apple Reminders, and more!
Powerful and flexible
Filters, tags, lists, infinite-depth subtasks, manual sorting. Tasks works with nearly any productivity system!
Customizable and mutilingual
Extensive options for customizing the look and feel of Tasks. Use Tasks in your language
Multiple sync options
Synchronize with Tasks.org, Google Tasks, DAVx⁵, CalDAV, EteSync, or DecSync CC
Private
Use offline, self-host, or setup EteSync for end-to-end encryption. There are no ads and your data is never shared with anyone