Blur sensitive info in a screenshot before you share it.

Screenshots travel further than you expect. The one you drop into a group chat or paste into a shared doc often carries more than you meant to send: a colleague's email address, a customer's name, an API key sitting in a terminal. Arrowbox lets you blur those parts before the file leaves your machine.

The mechanics are simple. Paste the screenshot, drag a box over the sensitive bit, choose Blur, and turn the strength up until it is unreadable. It all happens in your browser — a single HTML page that makes zero network calls after it loads. Nothing is uploaded, which matters when the whole point is hiding something.

Blur strength is measured in the image's own pixels, not your screen's, so what you see on the board is exactly what lands in the exported PNG, JPEG or PDF. And the export is flattened — the blurred pixels are the only pixels in the file.

Open Arrowbox — free, no sign-up

Runs in your browser. Nothing is uploaded — zero network calls, enforced by the page’s Content-Security-Policy. Desktop browsers work best.

How it works

Add the screenshotPress Ctrl+V to paste it straight from the clipboard, drag the file onto the board, or click Open. Several screenshots can sit on one board if you have a batch to clean.
Pick the redaction tool and set the mode to BlurThe same tool also offers Pixelate and Solid black, but for softening a name or a face in context, Blur is the one you want.
Drag a box over the sensitive partCover the email address, the account number, the face. Drag as many boxes as you need — each one blurs the area beneath it.
Adjust the strengthTurn it up until the content is unreadable even when you zoom in. Strength is set in the image's own pixels, so the export will match the preview exactly.
Export or copyHit Export (Ctrl+S) for a PNG, JPEG or PDF, or use Copy to put a flattened image on the clipboard, ready to paste into chat. The blur is baked into the output.

Why Arrowbox

Zero network calls after the page loads — enforced by an automated build gate, not just promised. Your screenshot never leaves your machine.
Blur strength is set in image pixels, not screen pixels, so the exported file looks exactly like the preview.
Exports are flattened: the blurred pixels are the only pixels in the PNG, JPEG or PDF.
No account, no sign-up, no watermark, no telemetry. Free, donation-supported.
Pixelate and solid-black modes sit in the same tool for the times blur is not enough.
Works offline — save the page from your browser ("HTML only") and it runs from a USB stick or an air-gapped machine.

Questions

Is blur safe for hiding text?

A strong blur is fine for casual sharing. But blurred text can sometimes be partially reconstructed, especially at low strength in a common font. For passwords, API keys or anything you truly cannot leak, use Pixelate at a coarse size or Solid black instead — both sit in the same tool.

Can someone remove the blur from the exported image?

Not from the export. When you export a PNG, JPEG or PDF the image is flattened and the blurred pixels replace the originals — there is no hidden layer to peel back. One caveat: a saved .json project file does keep the original for re-editing, so share the export, never the project file.

Do I have to upload my screenshot to blur part of it online?

No. Arrowbox runs entirely in your browser — after the page loads it makes zero network calls, and the page's own security policy enforces that. It also works offline: save the page from your browser and it runs from a USB stick or an air-gapped machine.

Can I blur a face, or several areas at once?

Yes. Blur boxes work on photos as well as interface text, so a face in a screenshot is the same job as an email address. Drag one box per area — there is no limit — and raise the strength until everything under them is unreadable.