Best of
Best second brain apps
A second brain is a system. Systems need a person willing to run them.
The tools below are genuinely good. Most abandoned second brains weren't abandoned because the software failed, but because the maintenance outlived the motivation.
01 · How we judged
What actually matters here.
- Effort per save
- What must happen before a thing is safely in the system?
- Effort per week
- How much tending does the structure need to stay useful?
- Retrieval model
- Do you navigate to things, search for them, or describe them?
- Ownership
- Are the files yours, and do they work offline?
02 · The options
The list.
In no ranked order. Each one is genuinely better than the others at something.
Obsidian
Local markdown vaultPlain markdown notes you write and link, with a large plugin ecosystem.
- People who think by writing and want to own the files.
- It only remembers what you wrote down.
Heptabase
Visual thinking canvasCards on whiteboards for working a subject out visually.
- Learning something hard, on purpose, over weeks.
- Needs deliberate sessions to pay off.
Notion
Workspace and databaseFlexible pages and databases that can be shaped into almost any system.
- Structured, shared knowledge with other people.
- The flexibility is the maintenance.
Fabric
AI workspaceAn AI workspace that brings files, notes and meetings into one place to work on.
- Gathering material and actively creating from it.
- Broad, cloud-based, and a workspace to look after.
Shelf
Local-first memory layer for MacA native macOS app that reads what you save, screenshots, links, PDFs, images and notes, writes a short summary and topics on device, connects each save to the things it belongs with, and finds it again from a rough description.
- People on a Mac whose real problem is recall, and who want the library to stay on their own machine.
- Mac only, single machine, no canvas, no collaboration, no mobile app.
A second brain asks you to think twice. A second memory asks nothing.
03 · Where Shelf fits
Our own bias, stated.
Shelf isn't a second brain and doesn't want to be. There's no structure to design, because the understanding is done for you on device and retrieval starts from a half-memory.
If you do write, keep writing. Obsidian and Shelf sit together comfortably: notes you author, plus the raw material you never got round to.
04 · Questions
Common questions.
- What's the best second brain app in 2026?
- Obsidian for writers, Heptabase for visual thinkers, Notion for shared systems. If the maintenance is what keeps failing, a memory layer like Shelf is a different answer to the same complaint.
- Is Shelf a second brain app?
- No. Shelf is closer to a second memory: nothing to maintain, and it works on the things you saved without writing about them.
If this idea interested you…
Shelf V3 is out now
Shelf V3 is the current build. Shelf does not use automatic updates, so download the latest build here and install it over your current version.
This is intentional. Shelf is built around a local-first, privacy-focused philosophy. An automatic updater requires additional background processes, network connections, update infrastructure, and another system with permission to modify the app. We prefer to keep Shelf’s network footprint and background activity as small as possible.
Manual updates keep the process explicit: Shelf only checks the internet when a feature actually needs it, and you decide when a new version is downloaded and installed.