Istor and Obsidian, compared.
The friendliest comparison here: both are local-first, both keep your files yours, and the difference is what each one does with them.
Obsidian is a local-first knowledge base: plain Markdown files on your disk, bidirectional links between them, and a plugin system. Istor is a local research notebook: it ingests the sources themselves, retrieves passages, and answers questions with every claim cited. One organizes what you wrote; the other reads what you have not. The philosophies match and the jobs do not, which is why the two sit well on the same machine.
What Obsidian does well.
Obsidian bet on local files before that was fashionable, and it won a large following because of it. Your notes are plain Markdown in a folder, readable by anything, with no lock-in and no server. Linking notes together and seeing the graph of your own thinking is the core act, and the plugin ecosystem stretches the app into nearly any shape a note-taker wants. For building a personal knowledge base that outlives any company, Obsidian is a fine answer, and nothing here argues with it.
The boundary is the notes themselves. Obsidian's search covers what you have written into it, and the sources behind those notes live elsewhere.
Where Istor differs.
Istor starts from the sources, not from your notes. Papers, reports, transcripts and scans go in as files, and retrieval pulls out the actual passages a question needs. The answer arrives with citations to those passages, and a verification gate checks each claim against the passage it cites before you see it, refusing when the library does not contain an answer. Notes in Istor sit beside the sources they came from, but the note-taking is in service of the reading, not the other way around.
It is also a much smaller tool on purpose. Obsidian grew into a platform with thousands of plugins; Istor is a research instrument with a fixed shape: import, question, cite, note. That narrowness is a feature of instruments.
Side by side.
| Istor | Obsidian | |
|---|---|---|
| What it is | A grounded research notebook | A plain-text knowledge base |
| Core object | Your source documents | Your notes |
| Answers questions over documents | Yes, with citations and a verification gate | Searches your notes only; AI via plugins |
| Files | A local library you import to | Plain Markdown you own completely |
| Cloud | None, all local | Optional paid sync; the app itself is local |
| AI grounding | Built in: retrieval, citations, refusal | Plugin-dependent, bring your own model |
| Price | Free, open source | Free for personal use, commercial license for work |
Which one fits.
If your work is thinking in writing, building linked notes over years, Obsidian is the tool and this page is not arguing otherwise. If your work is getting through sources and being able to trust what comes out of them, that is the job Istor was built for.
They also compose. A working loop is to question the sources in Istor, verify the citations, and write the findings into Obsidian, where they link into everything else you know. Reading in one place, remembering in the other, both offline, both on your disk. Writing with sources on a local AI is the closest thing to this loop, and Zotero slots in on the references side.