Productivity · Open source

Cobalt

Hanan Bhatti

Universal offline-first note capture and personal knowledge archive

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Opens the official F-Droid page

Cobalt screenshot 1Cobalt screenshot 2Cobalt screenshot 3

About Cobalt

Cobalt is an offline-first personal archive and capture app for Android. It stores links, notes, images, audio clips, code snippets, and movie/anime watchlists in a local Room database without requiring an account.

Capture Methods:

- Android Share Target: Save text, URLs, images, and videos directly from other apps via the system share sheet.

- Floating Overlay: Access a screen-edge panel to write quick notes, capture links, or trigger OCR without leaving your current app.

- Screen Region OCR: Capture a screenshot or crop a region on screen using MediaProjection to extract text and links.

- Quick Settings Tile: Launch OCR capture directly from the system Quick Settings panel.

- Voice Notes: Record audio memos with real-time waveform display, stored locally on device.

- Home Screen Widgets: View recent captures or trigger capture actions from your home screen.

Organization & Viewing:

- Supported Item Types: Links (with metadata previews), Markdown text notes, Photos/Images, Video clips, Code snippets, Audio recordings, and Movies/Anime.

- Folders & Archive: Organize items into custom folders or archive them to remove them from the main feed while keeping them stored.

- Search & Filters: Search across titles, content, extracted OCR text, and URLs, with filter chips for each media type.

- Media Hub: Track movies and anime with watch statuses (Plan to Watch, Watching, Completed), genres, ratings, and release years.

- Storage Management: View local storage usage broken down by media type, with options to delete cached files.

Network & Privacy Disclosures:

The FOSS build stores all data locally on your device. It does not include analytics, tracking SDKs, or background synchronization services. Certain optional features connect to external APIs:

- AI Screen OCR & Transcription: Sends selected image regions or voice notes to Google's Gemini API for processing. This requires you to provide your own Gemini API key in Settings.

- Movie & Anime Data: Queries The Movie Database (TMDb) and Jikan (MyAnimeList) for media details and poster images. TMDb searches require your own TMDb API key.

- Trailers: Embedded playback of YouTube trailers on media detail screens.

What's new in 2.1.2

- Added opt-in toggle for GitHub update checks (default off in FOSS). - Fixed radial FAB menu to support direct tap selection. - Decoupled Home screen feed from Search tab query. - Completely removed sync/download background services from FOSS. - Added custom User-Agent and guidance for anime search. - Removed recurring backup notification dialog on note save.

How to install Cobalt

  1. Tap Download — the app's official page on F-Droid opens.
  2. Install it with the F-Droid app (recommended, for automatic updates), or use the download button on that page.
  3. If Android asks, allow the F-Droid app or your browser to install apps, then tap Install.
  4. Open Cobalt from your app drawer.

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