Seylo vs Obsidian

Thinking in writing. Obsidian keeps your notes as plain Markdown files on your own device, so they work offline, open in any editor and stay yours for as long as the files exist. Linking notes to each other, and seeing those links as a graph, is what it was built for, and years of writers, researchers and students have built their way of working on it.

It is free, for work too, and thousands of community plugins bend it to almost any method. If what you need is a place to write and connect your own ideas, a second brain, a research notebook, a Zettelkasten, use Obsidian. Seylo does not try to be that, and it keeps your projects on its servers rather than as files on your disk.

• It collects, not only writes. Pictures, pages, files and the answers worth keeping from ChatGPT or Claude go into a project as they are, saved with a right-click in the browser, a screenshot shortcut or the iPhone share sheet. Obsidian’s Web Clipper turns a page into a Markdown note; Seylo keeps the picture or the passage itself, with the page it came from.
• What came from what. Seylo records that this prompt came from that brief and this image from that prompt, and draws the chain on the project’s map without you writing a single link.
• What you decided. A short list of what the project treats as true, one current value for each with the older ones kept underneath, and approved work kept apart from drafts.
• References with a verdict. The Library keeps references outside any one project, each marked as worked or didn’t, with a line saying why, on islands you attach to the projects that should read them.
• Nothing to set up. The web app, the iPhone app and the browser extension all open the same projects. There is no vault to sync and no server to run.

Obsidian has no assistant of its own. Community plugins such as MCP Tools or Vault as MCP run a small MCP server next to your vault, so a desktop client like Claude Desktop can search, read and write your notes. Seylo has MCP built in: you paste one address into Claude’s connectors, ChatGPT’s, Cursor or Manus, approve it once, and it works in their web and desktop apps alike. See what a connected tool reads.

The bigger difference is what the assistant finds. In a vault it finds notes, and has to work out for itself which is current and which you abandoned. In Seylo it reads what the project has settled first, then the approved work apart from the drafts, and what came from what. It saves its own work back as drafts, cannot delete anything, and a suggestion that contradicts a decision waits for you rather than replacing it.

Checked on 5 October 2026. Obsidian is free without limits, for commercial use too; a commercial license at $50 per user per year is optional. Sync is $4 per user per month billed annually ($5 monthly), and Publish $8 per site per month billed annually ($10 monthly).

Seylo is free for three active projects, with the Library and the browser extension included, and Pro is $8.99 per month, billed annually, which is where connecting your AI tools lives. The whole list is on the pricing page.

Use Obsidian for what you think: the notes you write and link yourself. Use Seylo for what you make: everything a project gathers, where each thing came from, what you decided, and an AI that works from all of it. Plenty of people will keep both, and connect both to Claude.