KPeek

Quick Look for Dolphin. Tap Meta+Space on a file and it pops up. Tap again and it's gone.

• Quick, then gone. Pops up in a fraction of a second, showing Dolphin's own thumbnail while the full file loads. Close it and nothing keeps running: no background process, no tray icon.
• Previews nearly everything. Photos (HEIC, AVIF, JPEG XL, animated GIF/WebP), PDFs and comic books, video and music, code in 300+ languages, Markdown, 3D models, archives and fonts.
• Glide through folders. ← → walk the whole folder or just your selection. Ctrl+wheel zooms anything; drag to pan.
• Featherweight. Photos decode once at screen size (a 24 MP shot peaks around 225 MB), the graphics card does the zooming and the video decoding, and closing it frees everything.
• Sandboxed and private. A Flatpak that opens your files read-only and never touches the network.
• Any desktop. Plasma, GNOME, Xfce or a tiling window manager: if you use Dolphin, KPeek works.

Like PowerToys Peek for Windows Explorer and Sushi for GNOME Files, built for Dolphin.

KPeek runs as a Flatpak, so it works on any distribution with Flatpak, and with Dolphin on any desktop: Plasma, GNOME, Xfce or a tiling window manager.

From Dolphin (recommended). Open Settings → Configure Dolphin… → Context Menu → Download New Services…, search for KPeek and click Install. A terminal window shows the progress: it downloads KPeek, and the first time also the KDE runtime it runs on (a 400 MB download, shared with other KDE Flatpaks). Restart Dolphin afterwards. When a new version is out, the same dialog offers Update. The installer checks the download against the release's checksum.

By hand. Download kpeek-servicemenu-<version>.tar.gz from the latest release, then:

tar -xzf kpeek-servicemenu-*.tar.gz
kpeek-servicemenu/install-it.sh   # installs the newest KPeek Flatpak and adds "Peek" to Dolphin

The shortcut (Dolphin 26.04 or later): the installer binds Peek to Meta+Space, unless another Dolphin action already uses that key or you had already given Peek a shortcut. To change it, open Settings → Configure Keyboard Shortcuts in Dolphin and search for Peek. On GNOME, Super+Space switches the keyboard layout before Dolphin sees it: pick another key there. Without a shortcut, right-click a file and choose Peek.

Known issue (Dolphin 26.04–26.08): Peek's shortcut stops working after you change the theme, colour scheme, fonts, icons or accent colour, until Dolphin is restarted. Right-click → Peek keeps working. This is a Dolphin bug (KDE bug 522563), mostly fixed for Dolphin 26.12.

Uninstall from the same Download New Services dialog, or run kpeek-servicemenu/uninstall.sh. Either also removes the shortcut and forgets whether you hid Peek in Dolphin's context menu settings, so a reinstall starts shown.

With several files selected, KPeek moves through those; with one, through its whole folder. It works in the Trash too.

• Video plays badly or not at all with a broken GPU driver: start with QT_FFMPEG_DECODING_HW_DEVICE_TYPES=, to decode on the processor.
• Rendering problems with an unusual GPU: try QSG_RHI_BACKEND=vulkan, or QT_QUICK_BACKEND=software.
• Force the low-memory limits: KPEEK_LOW_MEMORY=1.

Dolphin has no plugin API for reading the current selection. KPeek therefore ships as a service menu: a "Peek" entry in Dolphin's context menu that receives the selected files. Dolphin 26.04 and later let you put a keyboard shortcut on a service menu action, so you can bind it under Settings → Configure Keyboard Shortcuts → Peek. The suggested shortcut is Meta+Space; plain Space already toggles Dolphin's selection mode.

KPeek shows one preview window at a time: the shortcut on another file switches it, and on the file being shown closes it. Closing the preview quits KPeek, so nothing stays in the background.

• Dolphin, on any desktop; Dolphin ≥ 26.04 for the keyboard shortcut (the context menu entry works with older versions)
• Flatpak
• To build from source: Qt ≥ 6.8, KDE Frameworks ≥ 6.10, Kirigami, Poppler (Qt 6), libarchive, libdbus, QtMultimedia, Qt Quick 3D, KSyntaxHighlighting. Optional: LibreOffice, for rendering every page of office documents

cmake -B build -G Ninja
cmake --build build
ctest --test-dir build
./build/bin/kpeek some-file.pdf

Development happens in a Fedora distrobox so the host system stays clean. To try a build from your real Dolphin:

scripts/dev-install-servicemenu.sh          # adds "Peek" to Dolphin, running ./build/bin/kpeek
scripts/dev-install-servicemenu.sh --remove # undo

Then bind the shortcut as described above and restart Dolphin.

To build the Flatpak bundle and the KDE Store package (needs flatpak-builder and the KDE 6.11 SDK):

scripts/build-flatpak.sh        # writes kpeek.flatpak and installs it for your user
scripts/build-store-package.sh  # writes dist/kpeek-servicemenu-<version>.tar.gz

Pushing a v* tag builds both and attaches them to a GitHub release. After rebuilding, close any open preview (or run pkill -x kpeek): an open preview keeps running the old binary. Set QT_FORCE_STDERR_LOGGING=1 to see Qt's messages in the terminal instead of the system journal.

Bug reports and pull requests are welcome on GitHub.

• Style: KDE's coding style, enforced by clang-format. Run cmake --build build --target clang-format before committing; the pre-commit hook that CMake installs checks it.
• Tests: add or update a test in autotests/ for logic changes (C++ with QtTest, UI behaviour as autotests/qml/tst_*.qml), and keep ctest --test-dir build green.
• Layout: src/ holds the C++ backend, with src/qml/viewers/ holding one QML file per preview type. A new preview type is a XxxViewer.qml plus a MIME rule in src/viewerresolver.cpp. Viewers take part in zoom, drag and keyboard scrolling by exposing zoom, scrollTarget and optionally dragPans and maxZoom (see src/qml/ViewerInput.qml).
• Licensing: the project follows REUSE: new files need SPDX headers (reuse lint checks).
• CI: every push builds and tests on Fedora; .github/workflows/ci.yml lists the exact dependencies.

Please follow the KDE Community Code of Conduct.

• Image, PDF, office, media, text/code, Markdown, archive, comic, 3D model and font viewers
• Universal zoom and grab-to-pan
• Flatpak, and one-click install from Dolphin's Download New Services (KDE Store)
• Flathub
• Polish: window resizes to fit images, pin the window size, settings

KPeek's maintainer directed its design and tested it on real hardware, and wrote it together with an AI coding assistant (Anthropic's Claude): most of the code, tests, packaging scripts and documentation were drafted with its help and reviewed, tested and revised before being committed. Commits it contributed to carry a Co-Authored-By: Claude line.

GPL-2.0-or-later. Build files are BSD-2-Clause. See LICENSES/.

The screenshots show KDE Plasma's "Next" wallpaper (CC-BY-SA-4.0, by the KDE Visual Design Group) and a photo of Moraine Lake by Gorgo (public domain).