Notesium
Notesium is an indexer for notes linked in both directions, intended for Zettelkasten and Evergreen methods.
What Notesium is
Notesium is an indexer for notes linked in both directions, intended for Zettelkasten and Evergreen methods. It keeps notes as plain Markdown files in one local folder, with offline access. In the web editor, typing `[[` opens a finder for inserting links; saved notes link back to each other. The Finder also searches the full text of notes. An interactive force graph shows note relationships and offers search filtering, previews, zoom, and layout adjustments. The embedded editor includes Markdown syntax highlighting, section folding, table formatting, and Vim mode emulation. Notesium also has a Vim and Neovim plugin that uses its CLI to find and preview notes. A local REST API can create, update, delete, retrieve, and list notes, but it is described as unstable and has no explicit versioning. Creating, updating, or deleting notes through the API requires starting the daemon with `--writable`. Notesium is free for personal and business use and open source under the MIT License. It supports Linux, macOS, Windows, web, and API access.
Good
- Stores notes as plain Markdown in one local folder
- Supports offline access
- Finder searches across all notes
- Graph includes previews and layout controls
- Free for personal and business use
Watch out
- REST API is described as unstable
- API has no explicit versioning
- API changes require the `--writable` option
Who it suits
Notesium suits people organizing personal notes, knowledge bases, research, journals, books, or workout tracking. It is also relevant to users who want locally stored Markdown notes with linked navigation and graph views.
Verdict
Notesium combines local Markdown storage with bidirectional links, full-text search, and a relationship graph. Its API has stated stability and versioning limitations, so users relying on API changes should account for those constraints.
Plans and prices
From Notesium's own pricing page, checked 15 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free | Free | Open source · MIT License · Linux, macOS and Windows · Free for personal and business use |
The facts
Each one read from Notesium's own pages, with the date it was checked.
What it does
- API
- The local REST API uses JSON and exposes endpoints to create, update, delete, retrieve and list notes.checked 15 Oct 2026
- API data model
- The documented note object includes filename, title, label status, incoming and outgoing links, timestamps, counts, path and content.checked 15 Oct 2026
- API stability
- The API documentation calls the interface unstable and says it has no explicit versioning.checked 15 Oct 2026
- API write control
- API writes are forbidden unless the daemon is started with the --writable option.checked 15 Oct 2026
- Bidirectional links
- Links create outgoing and automatically discovered incoming relationships between notes.checked 15 Oct 2026
- CLI
- Notesium includes a command-line interface with list, links, lines, finder, statistics, web and version commands.checked 15 Oct 2026
- Custom URI
- Notesium documents a custom notesium:// URI protocol for opening notes and actions.checked 15 Oct 2026
- Editor
- The embedded web editor supports Markdown syntax highlighting, section folding, table formatting, and Vim mode emulation.checked 5 Oct 2026
- File naming
- Note filenames use deterministic eight-character hexadecimal identifiers derived from Unix epoch time.checked 15 Oct 2026
- Graph
- An interactive force graph visualizes note relationships and supports search filtering, preview, zoom, and layout adjustments.checked 5 Oct 2026
- Graph view
- An interactive force graph visualizes relationships and supports filtering, previews, zooming and layout-force controls.checked 15 Oct 2026
- Installation
- Prebuilt binaries are provided for Linux, macOS and Windows, with SHA-256 checksum verification instructions.checked 15 Oct 2026
- Integrations
- Notesium provides a Vim/Neovim plugin that uses its CLI for note finding and preview.checked 5 Oct 2026
- Intended users
- The maker describes use cases including personal notes, knowledge bases, journaling, research, book writing, and workout tracking.checked 5 Oct 2026
- Knowledge models
- The product is designed for Evergreen notes, Zettelkasten workflows and personal knowledge management.checked 15 Oct 2026
- Labels
- A note with a one-word title is treated as a label and can organize linked notes into a taxonomy.checked 15 Oct 2026
- Latest release
- GitHub lists v0.6.5 as the latest release, published 20 July, with Vim/Neovim improvements and rewritten web tab management.checked 15 Oct 2026
- License
- The repository identifies the project as MIT licensed.checked 15 Oct 2026
- Linking
- Typing `[[` in the web editor opens a finder to insert a link, and saved notes are linked bidirectionally.checked 5 Oct 2026
- Link insertion
- Typing double brackets in the web editor or Vim integration opens a finder that inserts a Markdown link.checked 15 Oct 2026
- Local deployment
- The embedded web interface is self-contained and runs locally on the user's machine.checked 15 Oct 2026
- Performance
- The maker reports a 6.3 MB Linux build and 11.4 MB system memory for its web and API setup, noting that actual performance varies by system and usage.checked 5 Oct 2026
- Performance claim
- The official site reports an example Linux binary size of 6.3 MB, 11.4 MB total memory for web/API and 0.008 seconds for a sample CLI operation.checked 15 Oct 2026
The company
- Maker
- The site credits Alon Swartz in its copyright notice.checked 15 Oct 2026
Alternatives to Notesium
- 1
Mem Agent
Free planiOSWebAPIExtension8.2From $9 a month - 2
Supernotes
Free planAndroidiOSWebAPI8.2From £6 a month - 3
Obsidian
Free planAndroidiOSExtensionLinux8.1From $50 a year - 4
Logseq
Free planAndroidiOSWebLinux7.7From $5 a month - 5
RemNote
Free planAndroidiOS7.7From $8 a month - 6
SiYuan
Free planAndroidiOSWebExtension7.7$64 one-time