Build a linked knowledge base with wiki links

A folder of notes becomes a knowledge base when the notes point at each other. The folder tree tells you where a note is kept. Links tell you what it is related to, and that is usually the more useful question. mrkdwn gives you wiki links, backlinks, tags and a graph to answer it. This guide is about using them without turning note-taking into filing.

Link while you write, not afterwards

Type [[ and mrkdwn suggests notes to link to. Keep typing to narrow the list, then pick one. The link resolves as you type, so you can see at once whether it points at something real.

Line length matters more on screens than in print — see [[Line length and rhythm]].
The argument borrows from [[Bringhurst, chapter two]].

The best time to link is the moment the connection occurs to you, in the sentence that makes it. A link at the end of a note under “Related” says two notes are near each other. A link inside a sentence says why.

A wiki link is plain text in the file. Other Markdown tools that understand [[double brackets]] read the same syntax, and a tool that does not still shows readable text.

Keep notes small enough to link to

Links work best when each note is about one thing. A note called “Reading notes, September” is hard to link to because nobody knows which part you mean. A note called “Monospace for prose” is easy to link to, because the title is the claim.

You do not have to split everything up front. When you notice a paragraph you keep wanting to link to, that paragraph wants to be its own note.

Let backlinks show you what you did not plan

The backlinks panel (⌃⌘L on the Mac) lists every note that points at the one you have open. You wrote each of those links one at a time, but the panel shows them together, and that is where connections you did not plan start to show.

Open a note you have not looked at in a while and read its backlinks before the note itself. They tell you where the idea ended up being used, which is often more interesting than what you first wrote down.

Use tags for kind, and folders for place

Folders and tags answer different questions, so use both, lightly.

• Folders are where a note lives: Projects, Reading, Daily Notes. A note is in one folder. Give the folders you use most an icon and a colour, and favourite them so they sort to the top.
• Tags are what kind of note it is, or what state it is in: draft, question, recipe. A note can have several. The sidebar filters by more than one tag at once, and on iPhone and iPad a tag is a place you can open, with every note filed under it.

If you are not sure whether something is a folder or a tag, make it a tag. Tags are cheaper to change later.

Read the graph as a review tool

The knowledge graph (⌃⌘G on the Mac) draws the whole library as a force-directed web of notes and links. On a large library the whole graph is mostly texture. It becomes useful when you narrow it: filter by a tag or a search, and the graph shows only that corner of the library and how it connects.

Some patterns are worth looking for:

• Islands. A cluster that links only to itself is a topic that has not met the rest of your thinking yet.
• Hubs. A note with many links in may be doing the job of an index, or it may be three notes pretending to be one.
• Strays. A note with no links at all is either finished or forgotten. The graph cannot tell which, but you can.

Give every day a note

Daily notes are created for you, dated, every day you write. They are a good inbox: put the half-thought down in today’s note, and link it to a real note when it grows up. Because the daily note is dated, the link carries its own timestamp. Months later, a backlink from 2026-08-31 tells you when an idea first turned up.

Find anything in two keystrokes

Quick Open (⇧⌘O) fuzzy-finds any note by name. Full-text search is fuzzy across titles and headings and exact inside note bodies. Between the two, you rarely need to remember where you filed something. What you do need to remember is what it was about, and links help with that.

Where to go next

• A local-first Markdown editor for Mac, iPad and iPhone
• Sync Markdown notes between Mac, iPad and iPhone
• Write with AI and still know which words are yours

mrkdwn is on the App Store for iPhone and iPad. The Mac app is still in pre-release testing. See where each platform stands.