What Is Obsidian? Notes That Stay on Your Own Machine
Obsidian is a note-taking app, but what sets it apart is where it stores things: your notes don’t sit on a company’s servers, they sit on your own disk, as plain text files.
That single sentence matters more than it sounds. Delete the app tomorrow and your notes remain — because they are really just .md text files in a folder. Notepad, Word, even your phone’s file manager can open them.
What a vault is
The top-level unit in Obsidian is a vault. It sounds technical; it isn’t. A vault is a folder on your computer. Obsidian points at that folder and shows the Markdown files inside it as notes.
You can have several vaults — one for work, one for personal notes. Switching between them is just switching folders.
Three features that matter
Bidirectional links. When you link from one note to another, the target note also shows “this was linked from here”. Over time the notes form a connected web — a personal wiki.
Graph view. It shows how notes connect. At first glance it looks like a decorative toy; its real use is seeing how much you’ve accumulated on a topic and what is sitting isolated.
Plugins. There are thousands of community plugins — calendars, task management, tables, citation handling. There’s a trap here too, below.
What it costs
The desktop app is free and unrestricted. You don’t even need an account. There are two paid add-ons:
- Sync — cross-device synchronisation, end-to-end encrypted
- Publish — turning notes into a public website
You can solve syncing for free by putting the vault folder inside a cloud folder, which works in most cases. Obsidian’s own Sync handles conflicts more safely, but it isn’t required.
Who it suits, who it doesn’t
Suits: people who take notes consistently, who need to come back to them years later, who want their data to stay theirs, and who accumulate long-form writing and research. Consultants, lawyers, academics, writers.
Doesn’t suit: work where a team edits the same document simultaneously. Obsidian is designed for one person thinking; collaborative editing is not its strength.
The most common mistake
Most people who start with Obsidian spend the first week building the system: trying plugins, changing themes, designing a folder scheme. Then they stop without having written any notes.
The right way round is the opposite: open an empty vault and start writing. Folder structure emerges once you actually need it; a scheme designed in advance is almost always wrong.
Where AI comes in
Because the notes are plain text, they’re easy to hand to AI tools. Connecting your own vault to a model and asking “what have I written about this before” is the simplest form of the RAG idea. With notes locked in a closed format, the same job is far more work.
I build my own second brain on this principle — I described the system in a second brain for founders.
Frequently Asked Questions
Is Obsidian really free?
The desktop and mobile apps are free with no feature limits. Only Sync and Publish are paid, and both are optional.
Does it work offline?
Yes. Because the notes live on your device, it works entirely offline.
How is it different from Notion?
Notion is cloud-based and strong for teamwork; Obsidian is local and strong for solo, deep work. In Notion your data sits in their format; in Obsidian it’s plain text on your disk.
Can I move my data out later?
Yes — there’s nothing to move. The files are already yours and in an open format. Not creating app lock-in is the core design idea.
Does it handle non-English text?
Yes. The interface can be set to other languages, and since the content is plain text, accented and non-Latin characters are not an issue.