Bench guide

Blur sensitive text in a screenshot on Mac

Hide API keys, email addresses, and customer names in a screenshot before you share it — properly, not with a black rectangle anyone can move.

4 min read

You took a screenshot of an error to send to support, then noticed your API key is sitting right there in the URL bar. A quick rectangle in Markup feels safe — until you realise the recipient could probably move that rectangle aside in their own image editor and read what’s underneath.

Two paths

The free way (built-in macOS)

macOS’s Markup tool (the one inside Preview and the floating screenshot preview) doesn’t have a blur tool. You have two okay-ish options.

  1. Take a screenshot with ⌘⇧4, then click the floating preview before it disappears.
  2. Use the shape tool to draw a filled rectangle over the sensitive text.
  3. Set the fill colour to black and the line colour to match — so it reads as a solid redaction.
  4. Save. The shape is flattened into the PNG, so it can't actually be moved.

This is fine for casual hiding, but the result is a blocky black bar that looks unprofessional. There’s no real blur, and you can’t preview what the redacted version looks like before you commit.

The Bench way

Bench has a dedicated redact tool that pixelates the region — the pixels under it are actually replaced, not just covered.

  1. Take a screenshot with ⌘⇧2 (area) or ⌘⇧1 (full screen).
  2. The editor opens automatically. In the toolbar, click the Redact tool (the eye-with-a-slash icon).
  3. Drag across the sensitive text. Bench replaces the region with a pixelated patch.
  4. Want to adjust? Click the redaction to drag, resize, or delete it. Each one stays individually editable until you share.
  5. Hit Share. The exported image has the redacted regions baked in — they can't be recovered.

A couple of practical notes. First, redact generously. People can sometimes guess obscured text from context, so cover a bit more than you think you need to. Second, if you’re sharing via a Bench Cloud link rather than a file, the export that gets uploaded is the redacted version — your original (unredacted) PNG stays only on your Mac, in ~/Library/Application Support/com.generalsoftwarecorp.bench/captures/.

And if you later realise something slipped through, delete the upload from your Bench Cloud library. The bnch.sh link stops working immediately.

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