Syllepsis

Your notes. Your files. Your cloud.

Syllepsis is a free, open-source, local-first notes app. Your notes live as plain Markdown on your disk and sync through your own Google Drive — no vendor account, no subscription, no proprietary add-ons.

Download for your OS View on GitHub

Free & open source (MIT) · macOS · Windows · Linux · Android

Syllepsis editing a Markdown note next to a spatial world view

Local-first, by design

Every note is plain Markdown in a folder you control. Open them in any editor, back them up any way you like, keep them forever. Cloud sync runs through your own accounts with CRDT conflict handling, so edits from multiple devices merge cleanly. Private by default — nothing is uploaded unless you connect a provider.

AI that never leaves your machine

Semantic search and an optional local language model run entirely on-device. Ask questions of your notes and find things by meaning, not just keywords — with no data sent to any server, ever.

Power features, no lock-in

  • WASM plugins — extend the app with sandboxed WebAssembly modules.
  • Publish as a static site — turn a set of notes into a shareable website.
  • PDF import — bring documents in as editable notes.
  • Syntax highlighting — code blocks rendered by a plugin, not a service.

Download Syllepsis

Latest release · free & open source

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Open source, no telemetry

Syllepsis is released under the MIT license. There are no trackers, no analytics, and no phone-home. Read the code, file an issue, or send a patch on GitHub.

FAQ

Is it really free?

Yes — free and open source under the MIT license, with no paid tiers or add-ons.

Where are my notes stored?

As plain Markdown files in a folder on your device. Optional sync copies them to your own cloud account (e.g. Google Drive); Syllepsis never stores your notes on our servers because we don't run any.

macOS says the app is from an “unidentified developer.”

Early releases are not yet code-signed. Right-click (or Control-click) the app and choose Open, then confirm — macOS will remember your choice. Signed builds are on the roadmap.

Does the AI send my notes anywhere?

No. Semantic search and the optional local model run entirely on your device.

Can I sync between devices?

Yes. Connect the same cloud account on each device; edits merge automatically via CRDTs, even offline.