Outspline

Free plan Linux

What Outspline is

Outspline is a free, open-source modular outliner for Linux that organizes text items hierarchically. Its Organism add-on adds todo lists, task scheduling, and event reminders. Items can have multiple event rules, including complex recurrences, and event times can use local time or UTC. Schedule views can identify unallocated time and overlapping events, and can be exported as plain text.

Alarm notifications appear with a tray icon and can be snoozed or dismissed. Users can move among tiling, tabbing, schedule, and search views, customize global and contextual keyboard shortcuts, and adjust settings through a plain-text configuration file. Add-ons can be enabled or disabled. The software is distributed under the GNU General Public License version 3. The homepage lists version 0.8.4, released on 2018-02-04. The maker provides an Arch Linux package and manual installation instructions for other operating systems.

Who it suits

Outspline suits Linux users who want hierarchical notes alongside task scheduling and reminders. It may also fit users who prefer configurable shortcuts and add-ons.

What it does well

Free and open-source under GPLv3.
Supports complex recurring event rules.
Schedule views export as plain text.
Alarms can be snoozed or dismissed.
Keyboard shortcuts are configurable.

What to know first

Pre-packaged only for Arch Linux.
Homepage lists version 0.8.4 from 2018.
Other operating systems require manual installation.

Plans

Plan	Billed and limits	Price
Outspline	Free and open-source modular outliner · GPLv3	Free

As kynikos.github.io lists them, read 9 Oct 2026. The maker's own page has the final word.

Verdict

Outspline combines an outliner with scheduling and event reminders through its Organism add-on. Its Linux availability and listed release are important considerations.

Facts from Outspline's own pages

Add-ons: Outspline functionality can be extended with add-ons, which can be enabled or disabled as needed. · kynikos.github.io, 9 Oct 2026
Alarms: The application provides a tray icon and notifications for alarms, which can be snoozed or dismissed. · github.com, 9 Oct 2026
Availability: The maker's getting-started page says Outspline is pre-packaged only for Arch Linux and directs users of other operating systems to manual installation instructions. · github.com, 9 Oct 2026
Customization: The interface supports configurable global and contextual keyboard shortcuts and customization through a plain-text configuration file. · kynikos.github.io, 9 Oct 2026
Hierarchical notes: It stores text items hierarchically. · kynikos.github.io, 9 Oct 2026
License: Outspline is distributed under the GNU General Public License version 3. · kynikos.github.io, 9 Oct 2026
Purpose: Outspline is a modular outliner whose Organism add-on adds time management for todo lists, task scheduling, and event reminders. · kynikos.github.io, 9 Oct 2026
Recurring events: Items can have multiple event rules, including rules for complex recurrences. · kynikos.github.io, 9 Oct 2026
Release: The product homepage lists version 0.8.4, released on 2018-02-04. · kynikos.github.io, 9 Oct 2026
Schedule view: The schedule can highlight unallocated time and overlapping events, and schedule views can be exported as plain text. · kynikos.github.io, 9 Oct 2026
Support: The project lists a SourceForge forum, an Arch Linux forum thread, a mailing list, a bug tracker, and email as ways to contact the developer. · github.com, 9 Oct 2026
Time zones: Event times can use local time or UTC. · kynikos.github.io, 9 Oct 2026

Where Outspline stands on Freedom251

Outliner Software#23 of 31