Overmark
Draw over your screen, then capture it.
No telemetry, ever. Overmark sends nothing anywhere, has no account and needs no network access by default. Captures stay where you save them, and nothing is ever uploaded.
Overmark over a desktop with two windows, a chart of sign-ups this week and a launch plan. In Live, the chart keeps updating while a red pen circles its newest points. Then the screen freezes: the toolbar’s pause button turns into play and its backdrop shows a snowflake. A highlighter marks a line of the plan, an arrow points from it to the peak, and two numbered stamps are placed. A notice says the capture was copied and saved, and the layer closes.
What it is
Press a hotkey and a transparent layer covers the screen. Draw on it with a pen or a highlighter, then keep explaining (on a call, with the screen still moving underneath) or capture what you see with your drawing on it, to the clipboard and a file in one go. It replaces the “screenshot, save, open, annotate, save again” loop with one gesture.
Live, the screen keeps playing underneath: draw over it to explain something on a call. Frozen, the screen is held still, as a screenshot is, so you can mark up an exact moment and capture it. Switch between them at any time with F, and your strokes stay. Esc closes the layer, and the drawing goes with it: each time starts clean.
What it does
- Tools: a pen with pressure (with a mouse, speed sets the width), a highlighter that tints without covering text, arrows, rectangles, ellipses, lines, text, numbered stamps for steps in a bug report, an eraser and a laser pointer that leaves nothing behind
- Blur on a frozen screen, to hide secrets before you share
- Captures copied to the clipboard and saved as PNG (or JPG) in one go, by default to
Pictures\Overmark: the screen under the pointer (Ctrl+S), a region you drag (Ctrl+Shift+S), or without the drawing - A whiteboard and a blackboard (W), and a grid, dots or ruled lines under the ink (G)
- Disappearing ink for calls: strokes fade a few seconds after you draw them
- Undo and redo of at least 100 steps, a key for every tool and 1–9 for the colours; the hotkeys can be changed in Settings
Made for calls and screen shares
- The toolbar and the dim are hidden from screen sharing, so people on a call see your drawing but not the toolbar. Captures never include the dim, the toolbar or the notice.
- Waits in the tray using no CPU and opens in well under a tenth of a second, on every monitor: Win+Shift+D Live, Win+Shift+F Frozen.
- No keyboard or mouse hook: global hotkeys go through Windows’
RegisterHotKeyonly.
Ways to get it
Every release on GitHub has these downloads.
| Download | What it is |
|---|---|
overmark-<version>-x64.msi | The one most people want. Installs for you alone, with no admin rights, with a Start menu shortcut and an uninstaller. For IT, the same MSI installs per machine, silently: msiexec /i overmark-<version>-x64.msi ALLUSERS=1 /qn. |
overmark-<version>-portable.zip | Unzip it anywhere, such as a USB stick, and run overmark.exe: it keeps everything in that folder and writes nothing to the registry, unless you tick Start with Windows. |
SHA256SUMS.txt | Each download’s SHA-256, to check it before you run it. |
Before you use it
- Not code-signed yet, so Windows SmartScreen may warn the first time you run the installer or the exe: check each download against
SHA256SUMS.txt, then choose More info → Run anyway. - No automatic updates: “Check for updates” is off by default. Turned on, it only reads the latest release on GitHub and shows a link to it; it never downloads or installs anything by itself.
Open source
Overmark is free and open source under the MIT License.
© 2026 Darren Marshall. Overmark is independently developed and isn’t affiliated with, endorsed or sponsored by Microsoft. Microsoft and Windows are trademarks of the Microsoft group of companies.