Open source alternatives to Capacities

By GitHub stars it is SiYuan, with 47,216 stars and a commit on 13 Nov. Choose SiYuan when you want linked notes stored on your own device for free, and pay only if you need sync. Next come SilverBullet (6,525 stars).

Yes. The code of all 2 is public under AGPL 3.0 or MIT, so you can use them with no licence fee. Running one yourself costs the server and your time to look after it, and some makers also sell a hosted plan.

Start from the job you use Capacities for. Choose SilverBullet when your notes must stay plain Markdown files in a folder you control, readable without the app.

All 2: SiYuan and SilverBullet. Each tool's page says what it needs to run.

All 2 we track had a commit in the last 30 days, among them SiYuan and SilverBullet. A recent commit shows the project is kept up, not that it will stay that way.

AGPL 3.0 (1), MIT (1). MIT, BSD and Apache let you change and reuse the code freely. GPL and AGPL ask you to share your changes under the same licence when you give the software to others, and AGPL also counts letting people use it over a network.

The hosting. Capacities's maker runs the servers for you; with an open source tool the updates, backups, security fixes and support are yours, unless you take the maker's hosted plan. Features differ too, so check what each one imports and exports before you move your data.