Obsidian vs DEVONthink: Notes You Write vs Documents You Collect

This pairing comes up among academics, lawyers and long-horizon researchers, and the confusion is understandable because both promise "everything in one place." They mean different everythings. (Disclosure: we make a notes app, Clair Mind. Referee only.)

DEVONthink manages documents other people wrote. PDFs, scans, emails, web archives, images — OCR'd, indexed, classified, searchable, kept for decades.

Obsidian manages notes you wrote. Markdown files, linked to each other.

The distinction is source material versus your own thinking, and it decides almost everything about which one you need.

At a glance

What DEVONthink actually does

Two things justify the price and the learning curve.

It ingests anything and makes it findable. Scanned documents get OCR'd, emails get archived, web pages get captured as they were on the day you saw them, and everything is full-text searchable in one place. For anyone whose work involves a large body of documents they did not write — case files, primary sources, standards, correspondence — this is the core need, and general notes apps handle it badly.

"See Also and Classify." DEVONthink analyses text statistically and suggests documents related to the one you are reading, and where a new document probably belongs. This predates the current AI wave by many years and is still the feature users describe as uncanny: it surfaces the paper from four years ago you had entirely forgotten, on the basis of textual similarity rather than any tagging you did.

That is a genuinely different value proposition from linking. Links require you to have already noticed the connection. See Also finds ones you never made.

Its weaknesses are real: it is Mac-first with a weaker iOS companion, the interface is dense and dated, the sync options are a project of their own, and it is expensive. It is also a poor writing environment — you would not draft in it.

What Obsidian actually does

Obsidian is where you put what you concluded. Plain markdown files on disk, [[wikilinks]], backlinks and a graph, and increasingly database-style views through Bases. The files outlive the app, which matters on a research timescale — see plain text notes.

For building an argument over years, it is the better tool by a distance. A Zettelkasten is a structure of your own claims connected to each other, and DEVONthink has no real concept of that.

Obsidian's weakness here is symmetrical: it is bad at large binary documents. You can drop PDFs in a vault, but there is no OCR, annotation is limited, and a vault with 3,000 PDFs is unwieldy. It manages text you wrote, not a library.

The setup serious researchers actually use

Frequently both, with a clean division:

1. DEVONthink holds the corpus. Every PDF, scan and source, OCR'd and searchable. It is the filing cabinet.
2. Obsidian holds your notes about the corpus. Claims in your own words, linked, with a reference back to the document.
3. Link between them. DEVONthink items have stable URLs you can paste into a markdown note, so a claim points at the exact source.

That respects the real asymmetry: sources are read and searched, your notes are written and connected. Trying to force one tool to do both is where people struggle — a vault stuffed with PDFs, or a DEVONthink database being used as a thinking tool it was not designed to be.

The discipline that makes this work is the same one everywhere: keep what the source says separate from what you concluded. See literature notes and permanent notes.

Choose DEVONthink if

• Your work centres on documents you did not write, in volume.
• You need OCR, scans, email archiving and web capture in one searchable place.
• You want related-document suggestions rather than manual tagging.
• You are on a Mac and the material must stay findable for decades.

Choose Obsidian if

• Your value is in your own writing and the links between it.
• You need it on Windows, Linux or mobile.
• You want free, and files you own outright.
• You are building a long-running body of your own thinking.

Choose both if

You are a PhD student, an academic, a lawyer or a long-form writer working with a large source base. See the best notes app for PhD students for how this fits a full stack with a reference manager.

What neither catches

Both are Mac-desk tools for deliberate work. Neither is reachable in the two seconds when a connection between two sources occurs to you away from your desk — and those are the thoughts you most want. That gap is what Clair Mind is built for.

Related: Anytype vs Obsidian, NotebookLM vs Obsidian, and the wider note app comparisons.