A local-first note editor and planner with no database, no cloud and no accounts —
every note, task and dataset is a plain, RFC 5322 .eml file on your disk.
English · Русский
A desktop app for thinking. Each page is a real email-format file (.eml —
RFC 5322 / RFC 2045): open it in Thunderbird, search it with grep, diff it in
git, back it up with rsync, sync it with Syncthing. CapsuleCraft adds the
editor, search, planning and structure on top — and the files stay yours.
- 🗂 Zero database — a folder of
.emlfiles is the entire knowledge base. - 🛰 Offline by design — parsing, search, AI and planning all run locally; the app makes no network calls of its own.
- 🤖 Offline Co-Thinker — deterministic local critique and data analysis. No API keys, no cloud.
- 🧩 Downloadable local AI — OCR (Xiaomi-OCR-0 on a Rust engine), speech-to-text (whisper) and Russian text-to-speech install from the in-app Integrations catalog and run fully offline.
- 🖥 Tiny native shell — Rust + egui, no browser engine. Ships as an AppImage with zero bundled libraries.
CapsuleCraft starts empty — no demo notes, no filler. A built-in FAQ
(top bar ⓘ FAQ, F1, or the command palette) explains storage, search and
data transfer right inside the app.
| Page | Search (BM25) |
|---|---|
 |
 |
| Backlinks | Planning |
 |
 |
| FAQ (built-in) | Graph |
 |
 |
More views — threads, raw MIME, mail preview
| Threads | MIME inspector |
|---|---|
 |
 |
| Mail view | |
 |
- Block editor — headings, paragraphs, task lists, callouts, code blocks,
CSV datagrids, audio-attachment notes; autosave, undo/redo,
.emlround-trip. [[Wiki links]]— parsed from page text, clickable, with a live backlink index («Linked from»); renaming a page rewrites every link.- Search — Okapi BM25 over the whole vault with relevance scores, highlighted snippets and Cyrillic-aware case folding; «Related by meaning» ranks pages by tf-idf cosine similarity using the same index.
- Planning — every task block across the vault aggregated into Agenda, Kanban, Gantt (with dependency arrows and cycle protection) and calendar, with RFC 5545 ICS export.
- Threads — replies are real child
.emls withIn-Reply-To/References, exactly like email. Your reasoning tree is standard mail threading. - Datasets — CSV/JSON travel as MIME parts addressed by
Content-ID; datagrid blocks render them as tables — and=SUM(A1:A5)-style formula cells are evaluated by the embedded offline JS engine, both in the browser and in the native shell. - Native audio recording & playback — record voice notes right from the audio block (cpal → 16-bit PCM WAV, live level meter) and play MIME audio in the egui shell (rodio: WAV/MP3/OGG/FLAC) with play/pause/stop, scrub seeking and a volume slider.
- OpenPGP capsule encryption — any capsule can be exported as an armored,
passphrase-encrypted
.eml.asc(AES-256, SEIPD v1 via rPGP) and imported back with the same dialog; fully offline, no gpg binary required. - Offline code execution — JavaScript REPL blocks run in the native shell through the embedded boa engine (the web build uses a sandboxed worker); JSON blocks validate and pretty-print; Python/Rust stay honest about having no interpreter in a zero-dependency build.
- Import — drop
.emlfiles into the window (byte-for-byte), import from IMAP or migrate an existing Obsidian vault (--import-obsidian). - AI-agent ready — expose the vault over MCP so Claude, Cursor or any MCP client can read and search your knowledge base. The built-in Co-Thinker argues with your theses offline instead.
- Built-in FAQ + snapshot CLI —
--snapshotrenders the real window to PNG (which is how every screenshot above was made). RU/EN interface included, and the EN locale is enforced 100% Latin by a unit test.
Most apps lock your knowledge in a database that dies with the app. CapsuleCraft flips it: one page = one plain-text message on disk.
| Typical PKM app | CapsuleCraft | |
|---|---|---|
| Storage | closed database | plain .eml files |
| Opened by | the app only | any mail client, grep, git |
| Export | lossy conversion | the file is already the export |
| Migrations | App updates | never needed |
| Telemetry / accounts | varies | none — the folder is the app |
Message-ID: <capsule-1755000000000@vault.local>
Subject: Q4 pricing experiment
From: Owner <owner@vault.local>
To: Vault <vault@capsuleos.local>
X-Capsule-Tags: pricing, experiment
--capsule-boundary
Content-Type: application/json; name="blocks.json"
Content-ID: <blocks_json>
[{"id":"blk_1","type":"heading","data":{"level":1,"text":"Q4 pricing experiment"}}]
--capsule-boundary
Content-Type: text/csv; name="cohorts.csv"
Content-ID: <dataset_cohorts_csv>
cohort,users,conversion
Q4-A,1200,0.041
--capsule-boundary--The JSON part is the structured block canvas; extra parts are datasets and
attachments addressed by Content-ID from datagrid blocks. Threads ride on
standard mail headers.
| CapsuleCraft | Obsidian | OneNote | Notion | |
|---|---|---|---|---|
| Storage format | plain .eml (open standard) |
Markdown + hidden app data | proprietary binary sections | proprietary cloud database |
| Works fully offline | ✅ by design | ✅ | ||
| Account required | ❌ never | ❌ (paid sync needs one) | ✅ Microsoft account | ✅ for sync |
| Your data readable without the app | ✅ Thunderbird / mutt / grep |
✅ Markdown | ❌ | ❌ (export only) |
git-diffable, grep, rsync |
✅ native | ✅ | ❌ | ❌ |
| Real email threading | ✅ In-Reply-To/References |
❌ | ❌ | ❌ |
| Local deterministic AI | ✅ Co-Thinker | |||
| Open source | ✅ MIT | ❌ (free but closed) | ❌ | ❌ |
| Install size (Linux) | ~11 MB AppImage, no webview | ~100 MB Electron | 100+ MB | web app |
| Vendor lock-in | none | low | high | high |
Where Obsidian/OneNote win today: Obsidian's plugin ecosystem, OneNote's stylus/inking depth, Notion's collaborative cloud editing. CapsuleCraft is deliberately narrower: local-first storage you can trust for decades.
- Data outlives the app. Delete CapsuleCraft tomorrow — Thunderbird still opens every note. No migrations, no conversions, ever.
- Privacy is structural. No accounts, no telemetry, no API keys, no network calls. The AI runs offline because that's the only honest option.
- Small and fast. The native shell has no browser engine inside: an 8–12 MB AppImage, instant start, glibc-only dependencies.
- Honest launch. Starts with an empty vault and a built-in FAQ — no demo notes pretending to be data. Known gaps are tracked in LIMITATIONS.md, not hidden in marketing.
- A migration path. An Obsidian importer, IMAP sync and
.emlimport get real content in on day one.
The native AppImage (recommended, Linux):
chmod +x CapsuleCraft_1.9.0_amd64.AppImage
./CapsuleCraft_1.9.0_amd64.AppImage # default vault...
./CapsuleCraft_1.9.0_amd64.AppImage /path/to/vault # ...or your folderIt needs only glibc, an X11 or Wayland desktop and (for audio playback) ALSA —
no WebKitGTK, no WebView2, nothing else. Every GitHub release also carries
SHA256SUMS.txt.
The native Windows app (x64) ships as CapsuleCraft_native_1.9.0_x64.zip:
unzip it and run CapsuleCraft.exe. Standalone native egui shell, zero dependencies,
no WebView2 or installer required.
The native macOS app (arm64) ships as CapsuleCraft_native_1.9.0_arm64.app.zip:
unzip it, drag CapsuleCraft.app into Applications. It is ad-hoc signed; if
Gatekeeper blocks the first launch, run xattr -d com.apple.quarantine CapsuleCraft.app.
Legacy web/Tauri builds (Windows MSI / NSIS, Linux deb, macOS dmg) are still
published for parity (on Linux those need libwebkit2gtk-4.1-0). The Linux
AppImage, Windows portable zip, and macOS .app are the recommended
native builds — no browser engine, no webview libraries.
First launch shows an empty vault and the built-in FAQ. Press
F1, use theⓘ FAQbutton or ⌘K → FAQ. No demo notes are ever created.
git clone https://github.com/kostyk348/CapsuleCraft.git
cd capsuleos/native
cargo run --release -- /path/to/your/vaultNative-only requirements: Rust stable, no GUI toolkit dependencies.
cargo run --release -- --snapshot out.png --page 1 [--view app] [--search "query"] [--scroll 300]native/src/
main.rs entry, arg parsing, FAQ modal, snapshot CLI
cli.rs typed CLI surface
mail.rs RFC 5322 / MIME parsing & serialization
mime.rs part splitting, Media-Type registry, datasets
blocks.rs block tree <-> markdown-ish round trip
page.rs page model, ordering, tree
links.rs [[wiki links]], backlink index
graph.rs capsule relationship DAG
threads.rs In-Reply-To / References threading
planning.rs agenda / kanban / gantt extraction, ICS export
search.rs BM25 index over the whole vault
mcp.rs MCP server config for AI agents
sync_imap.rs IMAP account sync
secrets.rs keyring-backed account storage
i18n.rs RU / EN strings
...
views/ page, graph, mail, mime, planning, threads, palette
# native shell
cd native
cargo test # 135 unit tests
# legacy web engine
npm ci
npx vitest run # 172 tests| Version | What | When |
|---|---|---|
| v1.12.0 | Integrations: downloadable local OCR (Xiaomi-OCR-0 on the pure-Rust mistral.rs engine), whisper STT in-process, Russian TTS (piper via sherpa-onnx), native PDF + image viewers | 2026-11-01 |
| v1.11.0 | Polish: multi-blocker tasks in the web Gantt editor; undo + marquee multi-select on the native whiteboard; seek + volume in native audio playback | 2026-11-01 |
| v1.10.0 | Microphone recording from the native audio block (cpal → WAV, live meter); fixed audio file attachments never reaching the capsule; AppImage CI fix | 2026-11-01 |
| v1.9.0 | Roadmap trio in the native shell: audio playback (rodio), OpenPGP .eml.asc encryption (rPGP), code execution + grid formulas (boa); full English UI with a purism test |
2026-10-31 |
| v1.8.1 | Release pipeline rebuilt: native Windows portable build, pre-created release (no more lost artifacts), unified SHA256SUMS.txt, native test job in CI |
2026-10-27 |
| v1.8.0 | Two-tier header, Zen focus mode, wide canvas; macOS arm64 builds; AppImage hardening | 2026-10-26 |
| v1.7.0 | Built-in FAQ in the shell; no demo notes anywhere; README redrawn | 2026-10-25 |
| v1.6.0 | Native standalone AppImage (zero bundled libraries) | 2026-10-25 |
| v1.5.0 | Renamed to CapsuleCraft; native egui shell | 2026-10-23 |
| v1.4.0 | Planning (Agenda/Kanban/Gantt/ICS); email import | 2026-10-22 |
| v1.3.0 | Co-Thinker offline proposal engine | 2026-09-25 |
| v1.2.0 | BM25 search; Linux installers | 2026-09-15 |
| v1.1.0 | Real audio playback | 2026-09-05 |
| v1.0.0 | First Tauri release | 2026-08-16 |
See LIMITATIONS.md. Notably: audio playback covers
WAV/MP3/OGG/FLAC (browser-recorded webm/opus needs conversion), the JS engine
runs no timed side effects or I/O, and vault sync is still a manual folder copy.
- ✅ v1.0 – v1.9 (current milestone)
- ✅ Native code execution (REPL / JS table formulas) — done in v1.9.0 (boa)
- ✅ Audio playback in the native shell — done in v1.9.0 (rodio)
- ✅ GPG-encrypted capsules — done in v1.9.0 (rPGP, passphrase
.eml.asc) - ✅ macOS native builds in CI (arm64)
- ⬜ Optional end-to-end-encrypted vault sync (tamper/censor-proof, still zero-cloud)
PRs welcome — see CONTRIBUTING.md. Changes are tracked in
CHANGELOG.md.
- Konstantin (@kostyk348) — creator, architecture, native shell, releases
- kobaltGIT (@kobaltgit) — native UI and MIME parser, live vault watching, offline Co-Thinker, MCP server, Obsidian importer, hierarchy drag & drop, IMAP sync; current GUI redesign (two-tier header, Zen focus mode, wide canvas)
MIT — see LICENSE.
CapsuleCraft — your thoughts, stored as mail.