booru-viewer

A booru client for people who keep what they save and rice what they run.

Qt6 desktop app for Linux and Windows. Browse, search, and archive Danbooru, e621, Gelbooru, and Moebooru. Fully themeable.

Screenshot

Linux — Styled via system Qt6 theme

Supports custom styling via custom.qss — see Theming.

Features

booru-viewer has three tabs that map to three commitment levels: Browse for live search against booru APIs, Bookmarks for posts you've starred for later, Library for files you've actually saved to disk.

Browsing

• Supports Danbooru, e621, Gelbooru, and Moebooru
• Auto-detect site API type — just paste the URL
• Tag search with autocomplete, history dropdown, and saved searches
• Rating and score filtering (server-side score:>=N)
• Media type filter — dropdown: All / Animated / Video / GIF / Audio
• Blacklisted tags and posts (client-side filtering with backfill)
• Thumbnail grid with keyboard navigation, multi-select (Ctrl/Shift+Click, Ctrl+A), bulk context menus, and drag thumbnails out as files
• Infinite scroll — optional, auto-loads more posts at bottom
• Start from page — jump to any page number on search
• Page cache — prev/next loads from memory, no duplicates
• Copy File to Clipboard — Ctrl+C, works for images and videos

Preview

• Image viewer with zoom (scroll wheel), pan (drag), and reset (middle click)
• GIF animation, Pixiv ugoira auto-conversion (zip to animated GIF)
• Animated PNG/WebP auto-conversion to GIF
• Video playback via mpv (MP4, WebM, MKV) with play/pause, seek, volume, mute, and seamless looping
• Info panel with post details, date, clickable tags, and filetype
• Preview toolbar — Bookmark, Save, BL Tag, BL Post, and Popout buttons above the preview panel

Popout Viewer

• Right-click preview → "Popout" or click the Popout button in the preview toolbar
• Arrow keys / h/j/k/l navigate posts (including during video playback)
• , / . seek 3 seconds in videos, Space toggles play/pause
• Floating overlay UI — toolbar and video controls auto-hide after 2 seconds, reappear on mouse move
• F11 toggles fullscreen/windowed, Ctrl+H hides all UI, Ctrl+P privacy screen
• Window auto-sizes to content aspect ratio; state persisted across sessions
• Hyprland: keep_aspect_ratio prop locks window to content proportions
• Bidirectional sync — clicking posts in the main grid updates the popout
• Video position and player state synced between preview and popout

Bookmarks

• Bookmark posts you might want later — lightweight pointers in the database, like clicking the star in your browser
• Group bookmarks into folders, separate from Library's folders
• Search bookmarks by tag
• Bulk save, unbookmark, or remove from the multi-select context menu
• Import/export bookmarks as JSON
• Unbookmark from grid, preview, or popout

Library

• Save posts you want to keep — real files on disk in saved/, named by post ID, browsable in any file manager
• One-click promotion from bookmark to library when you decide to commit
• Tag search across saved metadata — type to filter by indexed tags, no filename conventions required
• On-disk folder organization with configurable library directory and folder sidebar — save unsorted or to a named subfolder
• Sort by date, name, or size
• Video thumbnail generation (ffmpeg if available, placeholder fallback)
• Unsave from grid, preview, and popout (only shown when post is saved)
• Unreachable directory detection

Search

• Inline history dropdown inside the search bar
• Saved searches with management dialog
• Click empty search bar to open history
• Session cache mode clears history on exit (keeps saved searches)

Install

Windows

Download booru-viewer-setup.exe from Releases and run the installer. It installs to AppData with Start Menu and optional desktop shortcuts. To update, just run the new installer over the old one — your data in %APPDATA%\booru-viewer\ is preserved.

Windows 10 dark mode is automatically detected and applied.

Linux

Requires Python 3.11+ and pip. Most distros ship Python but you may need to install pip and the Qt6 system libraries.

Arch / CachyOS:

sudo pacman -S python python-pip qt6-base mpv ffmpeg

Ubuntu / Debian (24.04+):

sudo apt install python3 python3-pip python3-venv mpv libmpv-dev ffmpeg

Fedora:

sudo dnf install python3 python3-pip qt6-qtbase mpv mpv-libs-devel ffmpeg

Then clone and install:

git clone https://git.pax.moe/pax/booru-viewer.git
cd booru-viewer
python3 -m venv .venv
source .venv/bin/activate
pip install -e .

Run it:

booru-viewer

Or without installing: python3 -m booru_viewer.main_gui

Desktop entry: To add booru-viewer to your app launcher, create ~/.local/share/applications/booru-viewer.desktop:

[Desktop Entry]
Name=booru-viewer
Exec=/path/to/booru-viewer/.venv/bin/booru-viewer
Icon=/path/to/booru-viewer/icon.png
Type=Application
Categories=Graphics;

Hyprland integration

I daily-drive booru-viewer on Hyprland and I've baked in my own opinions on how the app should behave there. By default, a handful of hyprctl dispatches run at runtime to:

• Restore the main window's last floating mode + dimensions on launch
• Restore the popout's position, center-pin it around its content during navigation, and suppress F11 / fullscreen-transition flicker
• "Prime" Hyprland's per-window floating cache at startup so a mid-session toggle to floating uses your saved dimensions
• Lock the popout's aspect ratio to its content so you can't accidentally stretch mpv playback by dragging the popout corner

If you're a ricer with your own windowrules targeting class:^(booru-viewer)$ and you'd rather the app keep its hands off your setup, there are two independent opt-out env vars:

• BOORU_VIEWER_NO_HYPR_RULES=1 — disables every in-code hyprctl dispatch except the popout's keep_aspect_ratio lock. Use this if you want app-side window management out of the way but you still want the popout to size itself to its content.
• BOORU_VIEWER_NO_POPOUT_ASPECT_LOCK=1 — independently disables the popout's aspect ratio enforcement. Useful if you want to drag the popout to whatever shape you like (square, panoramic, monitor-aspect, whatever) and accept that mpv playback will letterbox or stretch to match.

For the full hands-off experience, set both:

[Desktop Entry]
Name=booru-viewer
Exec=env BOORU_VIEWER_NO_HYPR_RULES=1 BOORU_VIEWER_NO_POPOUT_ASPECT_LOCK=1 /path/to/booru-viewer/.venv/bin/booru-viewer
Icon=/path/to/booru-viewer/icon.png
Type=Application
Categories=Graphics;

Or for one-off launches from a shell:

BOORU_VIEWER_NO_HYPR_RULES=1 booru-viewer

Dependencies

• Python 3.11+
• PySide6 (Qt6)
• httpx
• Pillow
• python-mpv
• mpv (system package on Linux, bundled DLL on Windows)

Keybinds

Grid

Key	Action
Arrow keys / h/j/k/l	Navigate grid
Ctrl+A	Select all
Ctrl+Click / Shift+Click	Multi-select
Home / End	Jump to first / last
Scroll tilt left / right	Previous / next thumbnail (one cell)
Ctrl+C	Copy file to clipboard
Right click	Context menu

Preview

Key	Action
Scroll wheel	Zoom (image) / volume (video)
Scroll tilt left / right	Previous / next post
Middle click / 0	Reset view
Arrow keys / h/j/k/l	Navigate posts
, / .	Seek 3s back / forward (video)
Space	Play / pause (video, hover to activate)
Right click	Context menu (bookmark, save, popout)

Popout

Key	Action
Arrow keys / h/j/k/l	Navigate posts
Scroll tilt left / right	Previous / next post
, / .	Seek 3s (video)
Space	Play / pause (video)
Scroll wheel	Volume up / down (video)
F11	Toggle fullscreen / windowed
Ctrl+H	Hide / show UI
Ctrl+P	Privacy screen
Escape / Q	Close popout

Global

Key	Action
Ctrl+P	Privacy screen
F11	Toggle fullscreen

Adding Sites

File > Manage Sites. Enter a URL, click Auto-Detect, and save.

API credentials are optional — needed for Gelbooru and rate-limited sites.

Tested Sites

• danbooru.donmai.us
• gelbooru.com
• rule34.xxx
• safebooru.donmai.us
• safebooru.org
• e621.net

Theming

The app uses your OS native theme by default. To customize, copy a .qss file from the themes/ folder to your data directory as custom.qss:

• Linux: ~/.local/share/booru-viewer/custom.qss
• Windows: %APPDATA%\booru-viewer\custom.qss

A template is also available in Settings > Theme > Create from Template.

Included Themes

Each theme ships in two variants: *-rounded.qss (4px corner radius) and *-square.qss (no corner radius except radio buttons). Same colors, different geometry.

Settings

• General — page size, thumbnail size, default site, default rating/score, prefetch mode (Off / Nearby / Aggressive), infinite scroll, popout monitor, file dialog platform
• Cache — max cache size, max thumbnail cache, auto-evict, clear cache on exit (session-only mode)
• Blacklist — tag blacklist with toggle, post URL blacklist
• Paths — data directory, cache, database, configurable library directory
• Theme — custom.qss editor, template generator, CSS guide
• Network — connection log showing all hosts contacted this session

Data Locations

	Linux	Windows
Database	~/.local/share/booru-viewer/booru.db	%APPDATA%\booru-viewer\booru.db
Cache	~/.local/share/booru-viewer/cache/	%APPDATA%\booru-viewer\cache\
Library	~/.local/share/booru-viewer/saved/	%APPDATA%\booru-viewer\saved\
Theme	~/.local/share/booru-viewer/custom.qss	%APPDATA%\booru-viewer\custom.qss

To back up everything: copy saved/ for the files themselves and booru.db for bookmarks, folders, and tag metadata. The two are independent — restoring one without the other still works. The saved/ folder is browsable on its own in any file manager, and the database can be re-populated from the booru sites for any post IDs you still have on disk.

Privacy

booru-viewer makes no connections except to the booru sites you configure. There is no telemetry, analytics, update checking, or phoning home. All data stays local on your machine.

Every outgoing request is logged in Settings > Network so you can verify this yourself — you will only see requests to the booru API endpoints and CDNs you chose to connect to.

Support

If you find this useful, consider buying me a coffee:

License

MIT