A tool for taking associative notes

Thinktool's associative note-taking makes interconnected notes simple to explore. Freely connect related notes together with bidirectional links, or organize notes into loose outlines with multiple parents. Thinktool is the right tool for understanding complex topics.

Multiple Parents

Any outliner lets you organize your notes into a hierarchy, but sometimes it's hard to choose where a note belongs. With multiple parents, you can add the same notes to multiple topics, and Thinktool will keep everything in sync.

Bidirectional Links

Use bidirectional links to associate related notes. When you type a link, Thinktool will automatically add a link in the other direction. They let you quickly connect related items while writing. You can always come back later and add more structure.

Seamless Exploration

Most notes only make sense in context. With Thinktool, you can see references and other parents right there in the outline – even references and other parents. Of course, you can still jump between items if you need to.

About Thinktool

Thinktool is my side project. I'm currently using it as my main note-taking app, but it may still be buggy and unstable.

I'm actively working on Thinktool. It may become a paid service in the future (aiming for ≤$5/mo.), but currently you can use it for free. Sign up here.

I'm also working on an offline app for Thinktool. You can download a early prototype.


Thinktool is directly inspired by outliners like Org mode, Workflowy and Dynalist. The difference is that Thinktool lets you put one item in multiple places, so you're not limited to a hierarchy.

Roam Research is another associative note-taking application, and it's much more polished than Thinktool. Roam supports bidirectional linking like Thinktool, but it doesn't have support for multiple parents.