Second brain in Notion: how to build one that still works outside Notion

To build a second brain in Notion, make one page with four sub-pages for Projects, Areas, Resources and Archives, keep your notes as ordinary pages inside them, link those pages to each other, and add a database only where you actually need to sort or filter, which for most people is the project list. That is the whole build, and it takes an afternoon.

The decision hidden inside it is pages or databases. Most second brain templates lean hard on databases joined by relations, and that is the choice that decides whether the brain can ever be read anywhere other than Notion: by an export, by a teammate you want to show one folder to, or by an AI assistant. I work on Baalda, a team second brain that stores notes as plain markdown files, so the part of this I care about is what happens to the brain once something other than Notion needs to read it. The short answer is that pages travel and databases mostly do not.

What is a second brain in Notion?

It is the same thing as a second brain anywhere: a place outside your head where you keep what you are working on and what you have learned, organised so you can find it again. The structure most Notion builds use is Tiago Forte's PARA, and his own definitions are short enough to quote in full. Projects are "short-term efforts (in your work or personal life) that you take on with a certain goal in mind". Areas are "important parts of your work and life that require ongoing attention". Resources are topics "you're interested in and learning about". Archives are "anything from the previous three categories that is no longer active, but you might want to save for future reference".

Notion gives you two building blocks to hold that: pages, which are documents that can contain other pages, and databases, which are tables whose rows are pages with properties attached. Every Notion second brain is some mix of the two. The method itself, and why it tends to stay personal, is covered in how to build a second brain. This post is the Notion build.

How do you build a second brain in Notion, step by step?

1. Create one top-level page called Second brain. Everything lives under it, which makes it one thing to share, move or export later.
2. Inside it, create five plain pages: Inbox, Projects, Areas, Resources, Archives. Plain pages, not databases.
3. Use Inbox as the only place you capture. A quick note, a pasted link, a half-formed idea. Do not file anything at capture time.
4. Under Areas and Resources, make one page per topic, and put notes inside them as sub-pages. Link notes to each other by linking to the page, so a note on a hiring decision points at the hiring area it belongs to.
5. Make Projects the one database. Give it a Status property and an Area property as a select. Each project is a row, and each row is a page you write in.
6. Once a week, empty the Inbox into the right place and move finished projects to Archives.

That is a complete second brain. It sorts the one thing that needs sorting (projects by status), and everything else is documents linked to documents, which is what notes are.

Should you start from a template or build it yourself?

Build the skeleton yourself and borrow ideas from templates, because a template's structure is a set of decisions you inherit without having made. The large ones tend to model everything as databases: notes, areas, resources and projects as separate tables, joined together. Notion's own help describes the two features doing the joining. A relation is "designed to help you express useful relationships between items in different databases". A rollup helps "aggregate data in your databases based on relations".

Those are good features. A dashboard that shows every open project in an area with a count of its notes is genuinely useful, and you cannot have it with plain pages. The cost is that the connections between your notes stop being links written in the notes and become properties Notion computes. That difference is invisible inside Notion and decides everything outside it.

What happens to a database second brain when it leaves Notion?

Notion's export documentation is plain about the shape of what comes out. "Any non-database Notion page can be exported as a Markdown file." For databases: "Full page databases will be exports as a CSV file, with Markdown files for each subpage."

So a page-built brain exports as a folder of markdown files that still read like notes. A database-built brain exports as tables of values plus loose pages. A CSV holds what each cell said on the day you exported. The board views, filters and rollup sums you used to navigate are things Notion works out while it is running, and a CSV is not a running Notion.

Two more lines from the same page matter if your brain is large or shared. Exporting nested pages as separate files depends on your plan: "If you're on a Business Plan or Enterprise Plan, you can switch on the Include subpages option." And the export only contains what the person exporting can open: "Pages that the exporter doesn't have access to, such as private pages of other users, will not be included in the export." If you are planning a move rather than a backup, the practical steps, including why Obsidian's importer asks for the HTML export instead of Markdown, are in moving from Notion to Obsidian.

What does an AI see when it reads a Notion second brain?

Everything you can see. Notion runs an MCP server so AI assistants can search and edit your workspace, and its help page states the scope directly: MCP tools "act with your full Notion permissions" and "can access everything you can access." It also says what the feature is for: "MCP works best for individual workflows where you're connecting your personal AI apps to your Notion workspace."

For a personal second brain in a personal workspace, that is the right grant. The brain is yours and the assistant reading all of it is the point. It changes the moment the second brain sits in a workspace with other people's pages in it, because the assistant's reach is your reach, not the reach of the brain. Connecting Claude to Notion goes through what that means in practice and what Notion's admin controls do and do not narrow.

What does the same second brain look like as plain files?

This is the build in Baalda, and the reason the pages-or-databases choice matters to me. The PARA structure from the steps above becomes a folder on your own disk:

Second brain/
  Inbox.md
  Projects/
    pricing-page-launch.md
  Areas/
    hiring.md
  Resources/
    pricing-research.md
  Archives/

Each note is a real .md file, and notes link to each other with wikilinks written in the text, so the connections are part of the note rather than a property beside it. Nothing needs exporting, because the files are already the format you would export to. Obsidian, a text editor or grep can open the same folder.

The two places a Notion brain gets awkward are the two Baalda is built around. Sharing is per folder and per file: share Projects/ with a colleague as an editor and keep Areas/hiring.md private, and when you both open the pricing page note you are typing in one document, merged keystroke by keystroke over a CRDT, rather than two copies. And an AI assistant connects over MCP to the same files under the same rules. Baalda's MCP server describes its list_notes tool as listing the "notes you can access in a vault" with "your permission" on each, and search_notes searches "everything you can access". Access is resolved per file on the server, so scoping what the assistant reaches is the same act as scoping what a person reaches. Writes are careful too: read_note returns a revision, and edit_note called with that revision refuses the change if someone edited the note in between, rather than overwriting them.

Baalda is open source under Apache-2.0, free to run locally and to self-host. The managed backend is free for 2 people and 1 synced vault, and the Team plan is $10 per seat a month, or $110 per seat a year, with a minimum of 3 seats.

When is Notion the better home for a second brain?

When the databases are the point. Baalda has no equivalent of Notion's relational databases, rollups, formulas or board and calendar views. If your second brain is mostly a task and project tracker, with dashboards counting things across tables, Notion does that well and a folder of markdown files does not do it at all.

It also wins on where you can reach it. Notion runs in a browser and on phones. Baalda ships desktop apps for macOS, Windows and Linux, with no mobile app, so a second brain you mainly capture into from your phone belongs somewhere else. And if you already pay for Notion and its AI, keeping the brain next to the rest of your work is a real advantage, not inertia. Baalda compared with Notion sets the two side by side.

How do you keep a Notion second brain portable?

If you build in Notion, a few habits keep the brain readable outside it, whatever you decide later:

• Keep notes as pages, not database rows. A page exports as a markdown file, and a row arrives as a line in a CSV.
• Use one database, for projects, and use a select property for its area instead of a relation, so the link survives as a plain label.
• Write links between notes into the text of the notes, so the connection is in the words rather than in a property.
• Keep the whole brain under one top-level page, so it is one export and one share, not many.
• Run an export once and open the result. Ten minutes with the files tells you more about what you own than any template description.

None of that costs you anything inside Notion. It just means the second brain you build there is still a second brain when something other than Notion has to read it.