Your Mac is a Zettelkasten note taking system

Originally an “analogue” index card system invented by a German academic, the zettelkasten (or slip box) note taking method is the subject of hefty discussions on Reddit and other note taking forums as to whether the best software to manage a zettelkasten is Roamer, Obsidian, DEVONthink, Bear app, Ulysses, Drafts, or the new kid on the block, Craft. As much as it’s a pleasure to read the pro and cons, the essence of the zettelkasten is that it’s an interlinked, richly connected system of atomic information.

It’s the connectivity between those notes that is important. In that respect, you could be taking notes with whatever app you want on a Mac, as long as you have a system that will create links and backlinks between them. Most of the discussions on the online platforms revolve around whether an app is based on Markdown or plain text. Sure enough, you want to make sure you choose a note app that, at the very least, makes it dead easy to export your notes into a plain text file format.

Regardless, it remains to be seen if people who find your note in 100 or 200 years time from now will be able to open your files at all.

Next to a text or Markdown editor, you’ll want to have a text expander such as Typinator. The reason being that, once again, ideally, you will need to add standardised headers, links and footers to your notes so you can interconnect them and remember what their context is. Typinator, for example, allows me to create an expansion for my shortcut “zetteltime” that expands the current time accurately to the second and converted to hexadecimal (to get a shorter ID) via the inline JavaScript snippet {/JavaScript Math.floor(}.

One note taking app to rule them all?

To get everything linked together in a sensible way, Mac users have an advantage in that they can install a small app that runs in the background and links all kinds of content together no matter the original application.

Hook costs $19.99 for the Essentials and $34.99 for the Pro version (I recommend going Pro). It has been developed by CogSci Apps Corp., a Canadian company. Hook can link and backlink information from any app it directly supports — and those are many — or which support scripting — and those are even more. The Pro version supports Markdown links, Hook files, and Search links.

What Hook allows you to use several different note taking apps, text editors and other software, and link between them. Let’s say I can’t decide between Bear, Ulysses and Craft for writing my research notes. That’s OK if I have Hook, because it doesn’t really matter from the zettelkasten point of view what I use to write my notes and how I connect them.

Hook also doesn’t fence you in as the links are standard hyperlinks, not some concoction that only Hook understands.

Even if you settle down for one single note taking app, Hook lets you link notes bi-directionally with anything else, including mind maps, web pages, calendars, PDF readers, reference managers, email apps, task and project managers, etc, etc. That basically means that Hook turns your entire Mac into a zettelkasten system.

Knowledge management

Even better, with Hook your Mac can be a knowledge management system for any sort of purpose, be it health, science, philosophical pondering, literature, or anything else that makes you tick intellectually. But how exactly does the zettelkasten method promote knowledge?

According to Wikipedia: “The zettelkasten (German for “slip box”) is a knowledge management and note-taking method used in research and study. A zettelkasten consists of many individual notes with ideas and other short pieces of information that are taken down as they occur or are acquired. The notes are numbered hierarchically, so that new notes may be inserted at the appropriate place, and contain metadata to allow the note-taker to associate notes with each other. For example, notes may contain tags that describe key aspects of the note, and they may reference other notes. The numbering, metadata, format and structure of the notes is subject to variation depending on the specific method employed.”

German social scientist Niklas Luhmann used index cards — many a scientist after him will have done the same until digital systems made it easier. Obviously, creating and using a zettelkasten has been made easier with the introduction of personal digital systems.

The method not only allows a researcher to store and retrieve information related to their research, but also enhances creativity. Cross-referencing notes through tags — or via links and backlinks — allows the researcher to perceive connections and relationships between individual items of information that may not be apparent in isolation. These emergent aspects of the method make the zettelkasten somewhat similar to a neural network with which one may ‘converse’.


The crucial component of a successful zettelkasten system is the atomic note, which is defined as a note that focuses on only one idea or concept. Most digital note taking apps make it difficult to concentrate on one idea only. They stimulate you to ramble on forever. I have yet to come across an app that only accepts, let’s say, 600 words at the most. However, some note taking apps make it easier to restrain yourself from writing until you drop. As Craft is based on the block concept, it is almost natural to write about a single idea per block.

In a digital zettelkasten, you can easily and efficiently recreate the atomicity with its indexing feature by using Typinator to make a shortcut that adds a date or unique ID in whatever format you wish — hexadecimal, Unix epoch date, UUID, etc. I created a full YAML compliant header block that contains the ID, tags and title in Typinator.


You can use virtually any editor on the Mac to create a zettelkasten if you have Hook installed. With Craft’s automatic backlink functionality and the way its block concept has been implemented, I found you get the ability to expand single-paragraph atomic ideas into full pages. Craft’s ability to expand blocks into full notes even makes it easy to create notes only that contain entire lists of related notes.

Craft still falls short when it comes to capturing web page content. I find that Bear so far is the only one that does it right. From Bear, you can export these notes to Markdown with images linked to in separate folders. I found it easy to import those Markdown notes into Craft, complete with the images in all the right places.

DEVONthink Pro 3 — with its folder indexing power — is perfect for analysis purposes. It does not have tags/links graphing, but it does offer Concordance and a very, very powerful search feature.

Of course, if you prefer to have all your notes in one place that is specifically designed to replace a zettelkasten in digital form, you might prefer Roamer, The Archive or Obsidian. My point is that it isn’t necessary per se if you already have those other apps. Having tried Obsidian, I think it only offers the graphing part as an extra. By the way, Luhmann didn’t have that at all.

Zettelkasten image by Kai Schreiber from Münster, Germany – zettelkastenCC BY-SA 2.0, via Wikipedia.