FOMOsnap

I had FOMO about Omarchy and couldn't switch, so I brought its screenshot tool over instead.

FOMOsnap is a native macOS screenshot and annotation overlay: a macOS-only port of tobi/omasnap, which targets Wayland and Hyprland. It captures the display under the pointer before showing any window of its own, so the editor never appears in its own screenshot. Annotations stay movable, resizable vector layers, and captures export at the display's native backing resolution.

The annotation editor is upstream's, largely unchanged — which is why this port was possible at all. Capture, windowing, OCR, clipboard, notifications, and the global hotkey were rewritten against macOS frameworks.

Features

• Freeform region, window, full-monitor, and scrolling-region capture modes. Scroll capture stitches a tall (or wide) page: you scroll it, or Auto-scroll drives the wheel for you (Accessibility permission).
• A pointer-side readout that turns any drag into a ruler: the pointer position while the crosshair is idle, then the frame size in native export pixels while a region, a hovered window, or a crop handle is being sized.
• Window capture is a crop of the display frame. Overlapping windows stay visible; there is no second clean-window recapture.
• Select/move/resize layers, mouse-wheel scaling, and eight external recropping handles.
• Draw, type, resize, or carry a layer past the screenshot edge to grow the canvas. Framed growth is the default; G cycles to tight Overflow growth (only the sides needed by annotations, with no frame), then Image (the original canvas size, clipping every outside annotation). Shift+G cycles backward without changing layer geometry. New framed strips start in window gray with the original screenshot's card shadow. B cycles through the colorful backdrops, shadowed and flat window gray, and Off so a background can always be removed. Overflow with no backdrop leaves its added pixels transparent. Shift+B toggles the current shadow directly, and undo/delete can contract grown strips.
• Arrows, straight lines, smoothed freehand strokes, and translucent highlighter strokes that automatically match and stay straight across screenshot text (with freehand fallback), plus hollow or filled rectangles (optionally rounded) and ellipses, numbered markers, editable text in Neucha, JetBrains Mono, or Inter Display (plain, outlined, or on a readability pill), and secure redaction with opaque or randomized non-spatial mosaic output.
• Per-layer preset or custom colors (including highlighter ink), undo/redo history, one-click whole-image or drag-region OCR (the recognized text is shown beside the image and copied to the clipboard), mesh-gradient backdrops, and rendered drop shadows on standard backdrop cards.
• Cut tool: drag across a band of the image to remove it and collapse the gap, with a live preview and dashed seam marker while dragging; annotations shift to follow.
• Pin a finished capture as a bottom-right always-on-top window, launched from the same fomosnap executable and visible on every Space.
• Crash-resistant working documents under a private ~/Library/Application Support/fomosnap/: the original source image plus a sidecar JSON operation log. Undo still works after a crash or --file reopen. Saving and copying write a normal flattened PNG to the clipboard or ~/Pictures/Screenshots.
• PNG on the pasteboard alongside a native image flavour, so any app can paste it, plus timestamped files under ~/Pictures/Screenshots by default.
• Top chrome clears the camera housing on notched MacBooks.
• Open an image already on the clipboard directly in the annotation editor.
• A recents shelf: the select overlay stacks small cards of the last five captures along the right edge; hover to fan them out, click one to reopen it in the editor with its layers still editable instead of taking a new screenshot.
• A live selection surface: the desktop keeps updating under the dimmed overlay while FOMOsnap retains keyboard and pointer input. Region, window, and fullscreen still grab the display before the overlay appears, so hover, menus, and tooltips stay in the committed image. Switching the frontmost app (Cmd+Tab) drops that still and recaptures. Scroll capture stays live so the page can still move.
• Correct native-pixel export on fractional or integer-scaled monitors.

Platform scope

macOS 14 (Sonoma) or newer, Apple silicon or Intel. The floor is set by SCScreenshotManager and SMAppService, both introduced in 14.

Everything Wayland-specific was deleted rather than abstracted, so there is no Linux build in this fork. Use upstream for that.

Permissions

FOMOsnap asks for Screen Recording the first time it captures. macOS cannot grant this to a running process, so the first run explains, opens System Settings, and exits — grant it there and start FOMOsnap again.

Auto-scroll also needs Accessibility, so FOMOsnap can post wheel events into the page under the overlay. Manual scroll capture does not. The grant cannot take effect in a running process either: allow it, then start FOMOsnap again. The agent never asks for Accessibility at launch.

The permission is attached to the app's code signature, not its path. The default signature is ad-hoc, which has no stable identity: its hash changes with the binary, so every rebuild or brew upgrade looks like a different app and macOS asks again. That is also why stale FOMOsnap entries pile up in System Settings > Privacy & Security > Screen Recording — they are safe to remove.

To stop the re-asking, build with a real signing identity:

security find-identity -v -p codesigning     # what you have
make build FOMOSNAP_CODESIGN_IDENTITY="Developer ID Application: ..."

A self-signed certificate made in Keychain Access works too; it only has to be stable, not trusted by Apple.

Release signing and notarization

The public Homebrew release must use a Developer ID Application certificate and Apple notarization. Ad-hoc signatures are suitable for local development, but Gatekeeper blocks them and Screen Recording grants do not survive rebuilds. The release workflow signs only version tags, so pull requests do not need Apple credentials.

Before the first signed release:

1. Enroll in the Apple Developer Program and create a Developer ID Application certificate under Certificates, Identifiers & Profiles. Export the certificate and private key from Keychain Access as a password-protected .p12.
2. In App Store Connect, create a Team API key under Users and Access > Integrations > App Store Connect API. Download its .p8 file immediately; Apple provides the private key only once. Record its Key ID and the team's Issuer ID.
3. Add these GitHub Actions secrets to the repository: APPLE_CERTIFICATE_P12_BASE64, APPLE_CERTIFICATE_PASSWORD, APPLE_API_KEY_P8_BASE64, APPLE_API_KEY_ID, and APPLE_API_ISSUER_ID.
4. Add the exact certificate identity as the repository variable FOMOSNAP_CODESIGN_IDENTITY, for example Developer ID Application: Example, Inc. (ABCDE12345). Verify it locally with security find-identity -v -p codesigning.

Encode the two files without putting either private key in the repository:

base64 -i FOMOsnap-Developer-ID.p12 | tr -d '\n' | pbcopy
base64 -i AuthKey_KEYID.p8 | tr -d '\n' | pbcopy

Paste each result into its matching GitHub secret. The tag workflow imports the certificate into a temporary keychain, signs with hardened runtime, submits the app to notarytool, staples the ticket, and verifies it with Gatekeeper before publishing the archive. Create the next version only after all five secrets and the identity variable are configured; older releases remain ad-hoc signed and must be replaced by a new release.

The agent never asks for the permission at launch, only when a capture is actually taken. Asking at launch meant prompting at login, exiting because the permission was missing, and being restarted by launchd — prompting again, indefinitely.

Install

Homebrew

brew tap redox/tap
brew install --cask fomosnap

The cask installs the latest tagged, prebuilt app. Upgrade it with:

brew upgrade --cask fomosnap

The first cask install installs and starts the resident agent. On later upgrades, the cask reloads the agent if it is still installed, so the new binary takes effect immediately. If you ran fomosnap --uninstall-agent, upgrades preserve that choice; run fomosnap --install-agent to enable it again.

The cask installs FOMOsnap.app in /Applications and provides the fomosnap command through a wrapper that still launches the executable inside the bundle. Screen Recording is granted to the bundle identity, not to a copied binary.

The cask is defined in packaging/homebrew/fomosnap.rb; the tap holds a copy.

From source

Requires the Xcode command-line tools.

brew install qt ninja
git clone https://github.com/redox/fomosnap.git
cd fomosnap
make install

That builds FOMOsnap.app and installs it to /Applications. Set PREFIX to install elsewhere.

For a command-line entry point, write a wrapper that execs the executable inside the bundle:

printf '#!/bin/bash\nexec "/Applications/FOMOsnap.app/Contents/MacOS/FOMOsnap" "$@"\n' \
  | sudo tee /usr/local/bin/fomosnap >/dev/null
sudo chmod +x /usr/local/bin/fomosnap

A wrapper rather than a symlink, deliberately. Launched through a symlink, dyld reports the symlink as the executable path, so +[NSBundle mainBundle] finds no bundle at all — which silently disables notifications and --install-agent. execing the real path keeps the bundle identity, and with it the Screen Recording grant.

The resident agent and its hotkey

macOS has no compositor config to bind a key in, so FOMOsnap can hold one itself. The agent stays resident with no Dock icon, registers a system-wide shortcut, and shows the overlay with no launch cost, because Qt is already warm.

The default shortcut is Ctrl+Cmd+4. Cmd+Shift+3/4/5 all belong to the system screenshot tool, so the obvious keys were not available.

fomosnap --agent                          # foreground, to try it
fomosnap --agent --hotkey cmd+shift+2     # any modifier+key combination
fomosnap --install-agent                  # start it at login
fomosnap --uninstall-agent                # stop starting it at login

FOMOSNAP_HOTKEY sets the default. The key toggles: press once to open the overlay, again to dismiss it.

--install-agent writes a user LaunchAgent to ~/Library/LaunchAgents/com.fomosnap.FOMOsnap.agent.plist and loads it, so the agent starts at every login and is restored if macOS quits it during a permission change. --uninstall-agent unloads and removes it.

Two details that are load-bearing rather than incidental:

• The plist names --agent explicitly. Registering the app to launch at login instead would start it with no arguments, which means an ordinary capture — a selection overlay across the screen the moment you log in.
• It is a plain LaunchAgent, not SMAppService. SMAppService checks a code requirement that an ad-hoc-signed app in a Homebrew keg does not satisfy: launchd accepts the registration and then refuses to spawn it, failing with EX_CONFIG. A plain LaunchAgent works from any location.

After a Homebrew upgrade the cask reloads the LaunchAgent with the new /Applications/FOMOsnap.app executable, so the login item survives version changes and the running agent is refreshed.

Prefer your own launcher? Skip the agent entirely and bind fomosnap in Raycast, Shortcuts, or Karabiner. Every capture is a normal process launch.

CLI capture modes

Running without arguments opens freeform region selection:

fomosnap

Explicit starting modes:

fomosnap --capture-region
fomosnap --capture-window
fomosnap --capture-fullscreen

Scroll capture stitches a region that is taller (or wider) than the screen:

fomosnap --scroll

Drag a region, then pick a direction: Manual ↓ / → scrolls the page yourself while FOMOsnap captures each step, and Auto ↓ / → scrolls it for you, one acknowledged notch at a time, stopping when the page stops moving. The frames are aligned and stitched into one image and opened in the editor, where Cmd+wheel zooms and the wheel scrolls it.

Compatibility positional names are also accepted:

fomosnap region
fomosnap windows
fomosnap fullscreen
fomosnap smart       # maps to region selection

These options choose what is initially selected; the editor still controls whether the result is copied, saved, or both.

Quick output skips the annotation editor. Add --copy to copy only, --save to save only, or both flags to copy and save. Region and window captures output after selection; fullscreen captures output immediately. Quick output cannot be combined with --file, --clipboard, or --pin.

One instance, toggled by the same hotkey

Only one capture overlay runs at a time, guarded by a lock file in the runtime snapshot directory. Starting fomosnap while an overlay is open sends the running instance SIGTERM, which it handles with a clean Qt shutdown; the new process then exits without capturing. Pressing PRINT therefore opens the overlay and pressing it again dismisses it.

Every capture invocation dismisses this way, quick output included: --copy/--save while an overlay is open closes the overlay and outputs nothing, rather than screenshotting the overlay that is still on screen.

Editing an existing image is never cancelled this way: --file, --clipboard, or an image path stops the running instance, waits up to two seconds for the lock, and opens the editor on that image. That is how a pin's Edit button and a notification click always land in the editor.

A lock left behind by a crashed instance is removed and reclaimed. A lock file that cannot be read or written at all is reported on stderr instead of being mistaken for a running instance.

Exit codes:

Edit an existing or clipboard image

Point fomosnap at any readable image and it opens straight into the annotation editor with the whole image selected, skipping the screen-capture step:

fomosnap ~/Pictures/Screenshots/screenshot-2026-08-11_10-00-00.png
# or
fomosnap --file /path/to/capture.png

To open the image currently on the clipboard:

fomosnap --clipboard

The clipboard must offer readable image data. Text-only clipboard contents return an error instead of opening an empty editor.

File URLs are accepted too. A saved capture notification's "Click to edit" action launches fomosnap on the finished screenshot, so it can be reopened and re-annotated.

Recent captures

Every capture finished from the editor (copied, saved, or both) keeps its working document, source plus operation log, on a shelf of the five most recent under ~/Library/Preferences/FOMOsnap/fomosnap/State/recent/ (FOMOSNAP_RECENT_DIR overrides). The select overlay shows them as a small stack of cards on the right; hovering fans them out and clicking one reopens that capture in the editor, undo history intact, in place of a new screenshot. Finishing a reopened capture replaces its shelf entry.

Configuration (optional)

FOMOsnap has no settings UI and runs fine with no config at all. If you want to change where screenshots land or what they are called, create ~/.config/fomosnap/fomosnap.conf (INI format); every key is optional:

[output]
# Where saved screenshots go. Default: ~/Pictures/Screenshots
directory = ~/Pictures/Captures
# Filename pattern, without extension (.png is appended).
# Default: screenshot-{date}_{time}-{app}
filename = screenshot-{date}_{time}-{app}

[colors]
# Up to eight preset colors for the palette, and the initial custom color.
palette = #ff375f, #ff9f0a, #ffd60a, #30d158, #0a84ff, #bf5af2, #000000, #ffffff
custom = #ff375f

[background]
# An image used as a "Custom" backdrop. B (or the toolbar button) cycles
# through the four gradients, this image when readable, shadowed/flat window
# gray, and Off.
image = ~/Pictures/backdrops/desk.jpg
# Style a fresh capture starts with: none, off, slate, aurora, sunset, lagoon,
# violet, or custom. `none` still allows Framed canvas growth to add its
# automatic window-gray mat; `off` stays transparent. `custom` only takes
# effect once `image` above loads successfully.
default = custom

Filename tokens:

The default keeps the date first so the folder always sorts chronologically: screenshot-2026-08-23_14-05-09-firefox.png. Anything else in the pattern is literal text (screenshot- is just a string). A name that already exists gets -2, -3, … appended.

Environment overrides (FOMOSNAP_SCREENSHOT_DIR takes precedence over the config):

FOMOSNAP_SCREENSHOT_DIR="$HOME/Pictures/Captures" fomosnap
FOMOSNAP_OCR_LANGS="eng+deu" fomosnap
FOMOSNAP_OCR_LANGS="ja-JP+en-US" fomosnap

OCR runs on Vision, so there is no language data to install: every language the system recognizes is already available. FOMOSNAP_OCR_LANGS takes BCP-47 tags (en-US, fr-FR, zh-Hans) joined with +, and also accepts the old tesseract codes (eng, deu, jpn) for the common languages. Defaults to eng.

Controls

Capture selection

The desktop remains live under the dimmed selection overlay while FOMOsnap owns input. Tabs across the top of the overlay switch the capture kind: Region, Window, Scrolling Region, Fullscreen. All four are modes of the same overlay. Scrolling Region selects exactly like Region; once the region is drawn, the page inside it goes live and the scroll controls appear in place. The tabs stay up in the editor too: a tab there drops the edit and goes back to capturing in that mode, and a small Scroll capture button under the image turns the drawn region into a scrolling capture. The keys below do the same without reaching for the pointer.

Annotation editor

Pinned captures

P renders the current capture, writes it to a pin-<pid>-<n>-<random>.png under the runtime snapshot directory, and launches the same fomosnap executable in detached pin mode. Active pins stack from the bottom-right and can be dragged by the image background. The window stays visible on every Space without compositor window rules. It preserves the image aspect ratio, with a maximum width of one third of the screen and a maximum height of one half.

Pinning neither touches the clipboard nor writes to the screenshot directory; it is a fourth output alongside copy, save, and copy-and-save. P closes the editor and releases the single-instance lock immediately. Pins from separate captures accumulate as independent processes.

Hover the pin to reveal its controls:

Image and path copying go to NSPasteboard, which owns the data, so it stays available after the pin is closed. No font-based symbol set is required; the controls use the same vector icon renderer as the annotation toolbar.

Canvas boundary changes affect only preview and export clipping. The complete vector geometry stays in the operation log, so switching back to Overflow restores every off-canvas part of a layer.

Creation tools return to Select after one placement without selecting the new layer. In Select mode, arrows and lines show only their two endpoint handles; other layers show a selection boundary. The eight blue/white handles outside the image recrop its corners or edges. After the canvas grows, those crop handles remain on the original source frame.

Development and verification

make check

The smoke executable exercises region/window/fullscreen startup modes, capture selection, working-document persistence (source plus op-log JSON), annotation tools, undo/redo replay, vector movement and scaling, text editing, OCR, native-DPI output, endpoint-only line selection, annotation-driven canvas growth and clipping policies, external crop handles, and the native-pixel measurement readout on a scaled monitor.

It also runs process-lifetime checks that drive the real executable and fail if it does not exit within a deadline, covering the teardown and signal paths that in-process tests cannot reach.

make icon redraws assets/FOMOsnap.icns from tools/icon-generator.cpp; the icon is vector-drawn at every size rather than downscaled from one bitmap.

For live launch profiling, the binary has an opt-in millisecond trace from main() through the first completed overlay paint:

FOMOSNAP_PROFILE_STARTUP=1 ./build/FOMOsnap.app/Contents/MacOS/FOMOsnap 2>startup.log

The trace is completely silent by default.

.github/workflows/build-macos.yml runs the same make check build, smoke suite, and available static-analysis checks on a macOS runner, stages the app bundle, and uploads a versioned artifact. A v* tag also attaches that artifact to the corresponding GitHub release.

Acknowledgements

The capture and annotation workflow is inspired by three excellent screenshot tools:

• Shottr — fast region/window capture, OCR, and polished backdrops.
• Satty — a focused, native annotation workflow.
• Flameshot — selection-first capture and an approachable annotation toolbar.

Thanks to their authors and contributors for establishing the interaction patterns that made this project possible. FOMOsnap is an independent implementation and is not affiliated with those projects.

Project history

FOMOsnap is a fork of tobi/omasnap, which was itself extracted with git filter-repo from the original Omarchy system-customization repository. This fork keeps that history and replaces the Wayland platform layer with a macOS one; the annotation editor is substantially unchanged, which is why the port was possible at all.

Upstream is where to go for Wayland and Hyprland — this repository will not carry a Linux build.

The bundled Neucha, JetBrains Mono, and Inter Display fonts are distributed under the SIL Open Font License. Their provenance and hashes are recorded in assets/FONTS.md; their licenses are installed with the application.