Monochrome email client for Android — Jetpack Compose, Material 3 Expressive. No colour accents, no noise, just email.

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[!WARNING] Gmail API test-user quota (100 users). The app is not published on the Play Store. If Google shows "This app is blocked", the test-user quota is exhausted. Run from source with your own Google Cloud project, or use an Outlook account (no such limit).

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Features

Category	Highlights
Inbox	Pull-to-refresh, paginated scroll, swipe gestures (configurable L/R), long-press actions, bulk multi-select, smart sender grouping, snooze (1hr/tomorrow/weekend/next week), undo toast (4s), date headers, scroll position retention per tab, calendar badge for scheduled, mark-all-read
Conversation	Collapsible thread view, inline chain view (configurable), CC/BCC expand, thread connecting lines, alternating backgrounds
Search	Local client-side filter (subject/sender/snippet), server-side API search with pagination
Multi-Account	Up to 10 accounts (Gmail, Outlook, IMAP), unified inbox toggle, swipe-to-switch avatar, profile card
Compose	Reply/Reply-all/forward, CC/BCC, contact autocomplete, file attachments (any MIME), schedule send, undo send (5-30s configurable), send-as aliases, email templates, formatting toolbar (B/I/U/lists/quote), PGP encrypt & sign, WebView contenteditable editor
Settings	Hub-and-spoke navigation — Appearance (theme, font scale, dividers, compact, remote images, markdown, email colors), Inbox (swipe config, smart grouping), Compose (reply mode, confirm-send, undo window, templates), Navigation (dock size, tab editor), Notifications (sync frequency, per-account channels), PGP key management
PGP	Ed25519/X25519 key generation, ASCII-armored import/export, auto-decrypt + signature verification, passphrase-protected keys, encrypt & sign on outgoing
Detail view	HTML rendering (WebView, JS disabled), algorithmic dark mode (AndroidX WebKit), collapsible quoted text, responsive email detection, remote image blocking with per-email override, CSP default-src 'none', HTML sanitization (no Jsoup), inline image previews (max 280dp), attachment grid (2-4 columns), font scaling (0.8x-1.3x)
Notifications	Adaptive WorkManager sync (2min foreground, 15min backoff), per-account channels (sound/vibration), inline reply via RemoteInput, archive+undo from shade, parallelised multi-account sync
Micro-interactions	Spring physics throughout — press-scale on cards/buttons, animated dock tabs, bounce on theme selector, animateContentSize for expand/collapse, sent overlay animation, slide+fade navigation transitions

Account management

• Gmail — Android Credential Manager + Google Identity Services
• Outlook — MSAL 5.4.0 with silent token refresh
• IMAP/SMTP — provider presets (Gmail, Outlook, Yahoo, Zoho, Custom) with connection testing
• AES-GCM encrypted credential storage (Android KeyStore)
• Provider-scoped sign-out

Architecture

flowchart TB
    subgraph UI [Compose UI]
        Inbox
        Detail
        Compose
        Settings
        Auth
    end

    subgraph Data [Data Layer]
        Repo[EmailRepo]
        AuthMgr[Auth]
        SettingsDS[Settings]
    end

    subgraph Local [Local Storage]
        Room[(Room + SQLCipher)]
        DataStore[(DataStore)]
        KeyStore[KeyStore]
    end

    subgraph Remote [Remote]
        Gmail[Gmail API]
        Outlook[Outlook API]
        IMAP[IMAP/SMTP]
        Push[FCM Push]
    end

    UI --> Data
    Data --> Local
    Data --> Remote
    Push -.->|background| Data

Layer	Technology
UI	Jetpack Compose, Material 3 Expressive, Navigation Compose
Language	Kotlin 2.2
DI	Hilt
Networking	Retrofit 2, OkHttp 4
Database	Room + SQLCipher
Auth	Google Credential Manager, MSAL 5.4.0
IMAP/SMTP	Eclipse Angus Mail (Jakarta Mail 2.x)
PGP	PGPainless 2.0.3 (Bouncy Castle)
Images	Coil Compose
Markdown	Markwon 4.6.2
Background	WorkManager + ActionQueueManager
Secure storage	AndroidX Security Crypto

Getting Started

Prerequisites

• Android Studio Ladybug+
• JDK 17+
• Google Cloud project with Gmail API enabled
• Azure App Registration (Outlook/Microsoft Graph — scopes: Mail.Read, Mail.ReadWrite, Mail.Send, User.Read; redirect URI: msal{client_id}://auth)

Setup

git clone https://github.com/shrivatsav-0/monomail.git

Create secrets.properties for the playstore flavor:

GOOGLE_CLIENT_ID=your_web_client_id_here

Configure MSAL (optional — app/src/main/res/raw/msal_config.json):

{
  "client_id": "your_msal_client_id",
  "authorities": [{"type": "AAD", "audience": "AzureADandPersonalMicrosoftAccount"}],
  "redirect_uri": "msal{your_client_id}://auth"
}

Minimum SDK: 26 (Android 8.0).

Builds

Flavor	Description
playstore	Bundled with the developer's official Google OAuth Web Client ID. Push notifications via FCM.
github	Excludes private OAuth client ID. Google Sign-In temporarily disabled during OAuth verification — use Outlook or IMAP in the meantime.

./gradlew installPlaystoreDebug   # or installGithubDebug

Contributing

PRs welcome. Open an issue first for significant changes.

Fork → Branch → Commit → Pull Request

License

GPL-3.0

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Built by Shrivatsav