Sleek is an open-source todo app that makes use of the todo.txt format. sleeks GUI is modern and simple but still offers a decent set of functions which help users getting things done. sleek is available as a client for Windows, MacOS and Linux.

Users can add contexts, projects, priorities, due dates, recurrences or threshold dates to their todos. These todo.txt attributes can then be used in full-text search, as filters or to group and sort the todo list.

sleek manages and watches multiple todo.txt files continuously for changes, which makes it easy to integrate sleek with other todo.txt apps. Also users can switch to dark mode and choose from multiple languages.

Todos with due date or repeating todos will trigger notifications and completed todos can be hidden or archived into separate done.txt files. If users have tons of todos, a compact view can come in handy.