Chithi

A desktop email, calendar, and contacts client built with Tauri v2 (Rust) and Vue 3 (TypeScript).

Supports IMAP, SMTP, JMAP, CalDAV, and CardDAV with a Thunderbird-style three-pane layout. On desktop, passwords are stored in the system keyring (Secret Service, macOS Keychain, or Windows Credential Manager).

Why?

Need a client with first class support for OpenPGP. Also allowing doing Calendar in the application without a plugin :)

Features

• Multi-account support for Gmail, Microsoft 365, Fastmail, IMAP, JMAP, CalDAV, and CardDAV
• Email threading with In-Reply-To and subject-based fallback
• Calendar with day/week/month views, recurring events, and meeting invite handling
• Accept/Maybe/Decline meeting invites from email with iTIP replies
• Client-side message filtering rules
• HTML email sanitization (no scripts, no remote content by default)
• OpenPGP signing and encryption, including smartcard support
• Nextcloud Talk, Matrix / Element Call, and Zoom meeting integration
• Dark and light themes

Prerequisites

• Rust (stable toolchain)
• Node.js (v20.19.x or v22.12+)
• pnpm (v10; the repository pins the exact version)

System Dependencies

Arch

  sudo pacman -S --needed \
    base-devel \
    openssl \
    dbus \
    gtk3 \
    webkit2gtk-4.1 \
    libayatana-appindicator \
    pcsclite \
    librsvg \
    curl \
    wget

Debian / Ubuntu

sudo apt update
sudo apt install -y \
  build-essential \
  pkg-config \
  libssl-dev \
  libdbus-1-dev \
  libgtk-3-dev \
  libwebkit2gtk-4.1-dev \
  libayatana-appindicator3-dev \
  libpcsclite-dev \
  librsvg2-dev \
  curl \
  wget

Fedora

sudo dnf install -y \
  gcc gcc-c++ make \
  pkg-config \
  openssl-devel \
  dbus-devel \
  gtk3-devel \
  webkit2gtk4.1-devel \
  libappindicator-gtk3-devel \
  librsvg2-devel \
  curl \
  cargo \
  pnpm \
  pcsc-lite-devel \
  wget

macOS

xcode-select --install
brew install openssl

Tauri uses the built-in WebKit framework on macOS. The keyring crate uses the native Keychain — no extra dependencies needed.

Build & Run

git clone https://github.com/SUNET/chithi.git
cd chithi

# Install frontend dependencies
pnpm install

# Run in development mode (hot-reload frontend + Rust backend)
pnpm tauri dev

# Build a release binary
pnpm tauri build

The release binary will be in src-tauri/target/release/.

Running Tests

# Frontend tests (Vitest)
pnpm test

# Rust backend tests
cd src-tauri && cargo test

# Type-check frontend
pnpm exec vue-tsc --noEmit

Data Storage

Desktop application data is stored below the platform's local data directory:

Platform	Base directory
Linux	${XDG_DATA_HOME:-$HOME/.local/share}/chithi/
macOS	~/Library/Application Support/chithi/
Windows	%LOCALAPPDATA%\chithi\

Linux honors XDG_DATA_HOME. The exact macOS and Windows locations should be verified with packaged builds. Within the base directory, chithi.db is the SQLite database, chithi.log is the log, and each mail account has its own directory. Desktop passwords and OAuth tokens are stored separately in the system keyring. See the data-removal guide before deleting data manually.

Architecture

• Frontend: Vue 3 + TypeScript + Pinia (in src/)
• Backend: Rust + Tauri v2 (in src-tauri/)
• Mail: IMAP via imap crate, JMAP via raw reqwest HTTP
• Sending: SMTP via lettre (IMAP accounts), JMAP Submission (JMAP accounts)
• Calendar: JMAP Calendar + CalDAV via reqwest + uppsala XML parser
• Storage: Maildir on disk + SQLite index, passwords in OS keyring

See docs/adr/ for Architecture Decision Records.

To enable usage in your work/school O365

Ask the admin to allow the application for permissions.

App details:
- Name: chithi
- Type: Public desktop client
- Auth flow: OAuth 2.0 Authorization Code with PKCE
- Redirect URI: http://localhost

- Client Application ID: b5941cd4-0385-40f1-953a-2c3b36f2a331

Access model:
- Delegated permissions only
- Access is limited to the signed-in user’s own mailbox, calendars, shared calendars, and contacts
- No client secret is stored on the device
- On desktop, OAuth tokens are stored locally in the OS keyring

Requested permissions:

- Microsoft Graph: `User.Read`, `Mail.ReadWrite`,
  `Calendars.ReadWrite`, `Contacts.ReadWrite`, `Place.Read.All`
- Outlook: `IMAP.AccessAsUser.All`, `SMTP.Send`
- Sign-in: `offline_access`, `openid`, `profile`, `email`

License

GPL-3.0-or-later