Yes — and by default, with end-to-end encryption that's on without you flipping a switch. We use XChaCha20-Poly1305 with per-note keys wrapped by an account-level master key generated on your first device. Slate's servers store ciphertext; we cannot read your notes, decrypt your backups, or recover them if you lose your key (we'll remind you to back the key up). The encryption module is open-source on GitHub and has been audited by Cure53.

Yes. Slate is offline-first by design — the editor never round-trips to a server for normal operations, and your full note database lives on-device. When you reconnect, changes sync via CRDT, so concurrent edits from a plane and a coffee shop merge without conflicts or "which one wins" prompts. We test offline on a 9-hour SFO–FRA flight every release.

All four, plus Notion, Evernote, Day One, Standard Notes, and any markdown directory. Apple Notes uses the share extension; everything else accepts the export bundle. Frontmatter, links, attachments, code blocks, and tags are preserved on round-trip. The largest import we've handled was 142,000 notes from a Roam graph — took 18 minutes, came out clean.

CommonMark + GFM (GitHub Flavored Markdown), no proprietary dialect. The editor renders inline as you type — headings shrink, code highlights, todos become checkboxes — but the underlying file stays portable .md you could copy into any other tool. We support frontmatter, mermaid diagrams, math (KaTeX), callouts, and code highlighting in 188 languages via Tree-sitter. Backlinks use `[[brackets]]` and are stored in-file, not in a sidecar DB.

Yes — slate.app/web, full-featured, offline-capable via service worker. Most users live in the native app (iOS/Android/macOS/Windows/Linux), but the web client is the same code path: same editor, same shortcuts, same encryption. Works in any modern browser including Brave and Arc. Particularly nice for hopping onto a borrowed machine without installing anything.