Obsidian

Obsidian suits people who want a personal collection of notes that stays useful outside a single online workspace. The core app is free; the official Sync and Publish services are optional paid products.

Its flexibility can also become a distraction. Start with a few folders, ordinary notes and links between related ideas. Add a plug-in only when you can describe a repeated problem it solves. A complex setup is not automatically a better knowledge system.

Before using it across devices, choose a sync method and test conflict handling with unimportant notes. Keep backups separate from synchronisation, and think carefully before granting community plug-ins access to a sensitive vault. Obsidian is especially appealing for an individual writing and research practice; a team requiring a centrally managed collaborative workspace should compare alternatives. This assessment uses product documentation, not a long-term reliability test.