How to Blur Sensitive Info in a Loom Recording (Before You Hit Record)

The reliable way to keep sensitive information out of a Loom recording is to blur it in the page before you press record, so the video only ever contains blurred pixels. Loom has no tool to selectively hide one field inside a recorded frame, and fixing a leak afterward means re-recording or deleting the video. A browser extension that paints the blur into the page — like BlurFirst — bakes it into whatever Loom captures.

Loom is built for speed: hit record, talk through a page, share the link. That same speed is the risk. A real customer's email, a live API key, an unreleased price, or a Slack DM can sit in frame before you notice — and because Loom uploads and processes the video the moment you stop, there's no quick 'blur this spot' edit to save you.

Why fixing it after recording rarely works

Loom's editor is good at some things and simply can't do others. Once a secret is captured, your options are slow and lossy:

• Loom can trim the start and end and cut a section from the middle — but it can't blur a region inside a frame.
• To hide something that appears mid-video, you have to re-record that stretch or delete the video and start over.
• Once you've shared the link, viewers may have already opened it — deleting doesn't un-send what people saw.
• Downloading the file, adding a blur box in a separate video editor, and re-uploading defeats the whole point of a fast, one-take async tool.

Blurring before you record sidesteps all of it. The secret is never captured, so there's nothing to edit, redact or re-record — and nothing sensitive ever lands in the file Loom uploads.

Blur before you record, step by step

1. 1

   Open the page you'll walk through

   Your dashboard, CRM record, docs, spreadsheet or web app — whatever the demo is about.

2. 2

   Start BlurFirst

   Click the BlurFirst icon or press Ctrl/⌘ ⇧ Y. A small control bar appears on the page.

3. 3

   Hide what's sensitive

   Drag a box over a region, click a single element to blur just one field (a customer name, an invoice total), or click Scan (Pro) to auto-detect emails, phones, cards, SSNs and API keys locally.

4. 4

   Glance over the page, then record

   Do a quick scan of the frame, then start your Loom recording. Because the blur is painted into the page as real pixels, the .mp4 Loom uploads only ever contains the blurred version.

After vs before, side by side

What to blur in a typical walkthrough

• Product demos on real or seeded data — customer names, emails and phone numbers.
• Client walkthroughs — other clients' names in a sidebar, account IDs, internal notes.
• Billing and pricing — invoice totals, card last-4, unreleased or negotiated prices.
• Developer demos — API keys, tokens, .env values and Authorization headers.
• Chat and notifications — a Slack thread or Gmail message that scrolls into view.

If you record the same walkthrough often, set a per-site profile (Pro): BlurFirst remembers which regions to blur on that page and re-applies them automatically the next time, so recurring demos stay safe without redoing the setup each take.