Todoist

Amir Salihefendic built Todoist in 2007 as a side project while working as a developer in Chile. It's now used by 40 million people across 150+ countries and is the most-installed task manager on every platform. The natural language input ("Meeting with Sarah tomorrow at 3pm #work p1") parses dates, projects, and priorities instantly. Todoist's Karma system gamifies task completion, and the API powers 100+ integrations. Doist (the parent company) is fully remote, profitable, and has never taken VC funding — a rarity in SaaS. It does one thing (task management) and does it better than anyone.