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Built-in Option
How to Enable Slack's Own Dark Mode
Slack includes a free built-in dark mode. Here is how to turn it on — then see below for a more customizable alternative.
On desktop (slack.com)
Open Preferences
In Slack, click your profile picture in the top-right, then choose Preferences.
Open Appearance
Select the Appearance tab.
Choose Dark
Pick the Dark theme — or choose Sync with system to follow your OS.
On iPhone & Android app
Open Preferences
In the Slack app, tap the You tab, then Preferences.
Appearance, then Dark
Tap Appearance and select Dark.
Limitation: Slack's dark theme has fixed colors and no scheduling beyond system sync. Turn Off the Lights gives you custom colors and automatic day/night switching on Slack and every other site.
Slack Dark Mode Features
Everything You Need for the Best Slack Dark Mode
Turn Off the Lights is not just a simple Slack dark mode. It is a complete browser enhancement built to give you full control over how every website looks in the dark.
Consistent Slack Dark Theme
Apply a uniform dark theme to slack.com with your chosen colors — not just the fixed default theme.
Auto-Schedule Day/Night Switch
Set sunrise/sunset switching or custom hours. Slack dark mode turns on and off automatically without any manual intervention.
One Theme for All Websites
The same dark theme applies to every website — Slack, Instagram Web, Messenger, YouTube, Reddit, and beyond.
Choose Your Own Dark Colors
Pick background, text, link, button, and border colors independently. True black for OLED or warm dark for reading comfort.
Smart Detection
Turn Off the Lights detects when Slack has already applied its own dark mode and can skip double-layering automatically.
No Slack Data Access
The extension applies visual changes only. It does not read, store, or transmit any Slack content or account data.
How It Works
Enable Slack Dark Mode in Under 30 Seconds
Turn Off the Lights is available in every major browser store and takes less than 30 seconds to install and activate. No configuration needed — it works instantly.
Install Turn Off the Lights
Add the free extension from Chrome Web Store, Firefox Add-ons, Edge Add-ons, or Opera Add-ons.
Open slack.com
Navigate to slack.com in your browser with the extension installed.
Enable Night Mode
Open Options → Night Mode tab and toggle the Night Mode switch on.
Set Schedule & Colors
Choose custom dark colors and set an automatic day/night schedule so Slack dark mode switches without any manual effort.
Browser Support
One Slack Dark Mode Extension. Every Browser.
Turn Off the Lights is available across all major desktop browsers. Install it in one browser and your Night Mode settings sync automatically to others.
⬇ Install Free — Slack Dark Mode
FAQ
Frequently Asked Questions About Slack Dark Mode
Slack has a built-in dark mode in its settings. For a fully customizable alternative with custom colors and auto-scheduling, install Turn Off the Lights and enable Night Mode in Options.
Slack's theme applies to the whole app, all workspaces included. For custom colors and automatic scheduling, use the free Turn Off the Lights extension.
Slack's dark mode has fixed colors and requires manual toggling. Turn Off the Lights offers custom colors, automatic scheduling, and the same dark theme on every other website you visit.
Turn Off the Lights is a browser extension for desktop browsers. For mobile, Slack's own app dark mode is the recommended option.
On OLED screens, true black pixels use less power. A true-black custom theme from Turn Off the Lights Night Mode saves more than any fixed dark-grey theme.
Reload the page or update the Slack app, then check Slack's theme or display settings. If dark mode is missing or too limited, the Turn Off the Lights extension applies a dark theme to Slack in any desktop browser.
Why Turn Off the Lights
The Most Complete Slack Dark Mode Solution Available
While Slack does offer a built-in dark mode, many users searching for Slack dark mode want more control — custom colors, automatic scheduling, and a consistent dark experience that extends beyond Slack to every other website.
Slack Dark Mode with Custom Colors
Slack's built-in dark mode uses a fixed grey-blue color scheme. Turn Off the Lights lets you choose your own background color — pure black for OLED, warm dark for eye comfort, or any shade you prefer. Apply the same custom theme consistently across Slack and all other sites.
Automatic Slack Dark Mode Scheduling
Slack's built-in dark mode uses a fixed color scheme. Turn Off the Lights lets you choose your own background color — pure black for OLED, warm dark for eye comfort, or any shade you prefer. Apply the same custom theme consistently across Slack and all other sites.
One Extension, Dark Mode Everywhere
Slack is just one website. Turn Off the Lights applies the same Night Mode theme to every website you visit — Messenger, Instagram Web, WhatsApp Web, YouTube, Reddit, Wikipedia, and any other site — giving you a unified dark experience across your entire browser.
Open Source, Private, and Free — Always
Turn Off the Lights collects no personal data, displays no advertising, and charges nothing. The extension is fully open-source under the GNU General Public License Version 2 (GPLv2), with its complete source code available on GitHub for anyone to inspect. It has been in continuous development since 2009 and remains one of the most trusted browser extensions available, with millions of active users across all major browsers. Stefan Van Damme is the solo developer and has maintained the extension with monthly updates for over 15 years.
Dark Mode Guides
More Dark Mode Guides
Get the same dark experience on your other favorite websites and browsers: