How to Blur Slack During Screen Sharing (Hide DMs, Channels & Notifications)
Sharing your screen from Slack? Here's how to blur DM and channel names, message content, notification banners and link unfurls before you present — while keeping the one thread you need visible.
To blur Slack DMs and channels when sharing your screen, cover the left sidebar — the channel and DM names — and, if you're only demoing one message or thread, box-blur the surrounding conversation while you leave the relevant part clear. BlurFirst bakes the blur into the page as real pixels before you present, so DM names, private channels, notification banners and link unfurls stay hidden in Zoom, Meet, Teams, Loom or any recording — and Ctrl/⌘ ⇧ H hides everything the instant a message lands.
What Slack reveals during a screen share
- The sidebar — channel names (including private and sensitive-topic channels) and your DM list, naming exactly who you talk to.
- DM participant names — the header of a direct message shows the person or group you're chatting with.
- Message content — the conversation itself, including anything a colleague said candidly minutes before the call.
- Channel member names — the header and member list of a channel expose who's in it.
- Notification banners — an in-app toast slides in with the sender and a preview when a new message arrives.
- Thread previews and replies — the 'N replies' preview and the thread pane surface side conversations.
- Link unfurls — pasted links expand into title, description and image cards that can reveal documents, tickets or dashboards.
How to blur Slack before you share your screen
- 1
Open the channel or DM you'll show
Get Slack to the exact conversation you plan to present before the call starts.
- 2
Start BlurFirst
Press Ctrl/⌘ ⇧ Y. Everything happens locally; the only network call BlurFirst makes is a license check.
- 3
Box-blur the sidebar
Drag a rectangle over the entire left column so channel and DM names stay frosted no matter what you click.
- 4
Hide the header and unfurls you don't need
Element-click the channel or DM header to blur member and participant names, and box-blur any link unfurl card that exposes a document or ticket.
- 5
Keep panic ready for banners and huddles
Press Ctrl/⌘ ⇧ H to blur the whole page if a notification banner slides in, someone starts a huddle, or the wrong message scrolls into view.
New messages push the view — and how blur keeps up
Slack is constantly moving. A new message pushes the conversation up, notification banners appear over the top-right, and starting or joining a huddle changes the layout at the top of a channel. Because a box blur is anchored to a region of the page, it keeps covering that area — the sidebar, a header, an unfurl — even as messages scroll underneath and the DOM re-renders. That's more reliable than trying to hide one name, because the name moves. For the sudden events a fixed region can't predict — a banner, a huddle invite, an @mention that yanks you to another channel — the panic hotkey blurs the entire page in one keystroke, and you toggle it back when it's safe.
If your screen shows things like an API token pasted into a channel, or customer emails and phone numbers in a message, BlurFirst's Scan (Pro) detects those patterns locally and blurs them in one click. Scan matches patterns — emails, phone numbers, credit-card numbers, SSNs and API keys — not free-text names, so keep the sidebar box blur on to cover channel and person names.
| Slack element | Best gesture | Notes |
|---|---|---|
| Sidebar (channels + DMs) | Box/region blur | Anchored to the column; survives clicking between conversations |
| Channel/DM header names | Element blur | Hide who's in the room while messages stay visible |
| A single message or code snippet | Element blur | Click to hide one bubble, click again to reveal |
| Link unfurl / preview card | Box or element blur | Covers the document or ticket the link exposes |
| Pasted keys, emails, numbers | Scan (Pro) | Detects the pattern locally and blurs in one click |
| Notification banner / huddle popup | Panic (Ctrl/⌘ ⇧ H) | Blurs the whole page instantly, then toggle back |
Why Slack's own settings don't cover this
Slack lets you mute channels and pause notifications, but muting doesn't remove a channel from the sidebar, and pausing notifications only stops the OS-level desktop alerts — the in-app banner and the live conversation still render inside the tab. There's no built-in presenter mode that hides other people's names. Blurring solves it at the layer that matters: it changes what your audience sees, not what you can access, and the pixels are part of the page so screenshots of the shared feed are covered too. The honest limit: BlurFirst works inside the browser tab, so if you run the Slack desktop app instead of Slack in a browser, that native window isn't covered — a BlurFirst desktop app is in development.