Slack launches a dark mode for macOS, Windows, and Linux, with dark mode variants of all existing sidebar themes and a new “Nocturne” dark mode theme
dark mode is now available on the desktop app as well as mobile, for everyone. Read more: https://slackhq.com/... https://twitter.com/... @mattietk : Slack has dark mode and now all that effort you spent carefully cutting out your custom emojis onto transparent backgrounds has paid off and all your coworker's shitty white jpegs are held up for what they are. Sam Sheffer / @samsheffer : great but why'd it take them 5 years? where's IG dark mode? https://twitter.com/... Casey Newton / @caseynewton : The original Slack dark mode was when your boss would DM you “hey” and nothing else https://twitter.com/... Owen Williams / @ow : me: dark mode is dumb and a waste of dev time also me: flips on dark mode immediately https://twitter.com/...
Context & Ripple Effects
Dark mode has been arriving app-by-app through 2018–2019: Microsoft teased it in a December Outlook for iOS refresh, then began rolling it out across Outlook mobile and Office.com in late August, just two weeks before Slack's move. Slack closing the gap on desktop — macOS, Windows, and Linux at once, rather than one platform at a time — reads as keeping pace rather than leading.
What distinguishes Slack's version is completeness: dark variants of every existing sidebar theme, not a single forced palette, plus a new "Nocturne" option. That matters because sidebar themes are a signature Slack customization surface, and half-supported theming would break what users had built.
First-order effects
- Desktop users on all three platforms get dark mode immediately alongside existing mobile support, with their chosen sidebar theme preserved via its dark variant — and custom emojis cut out onto transparent backgrounds, a long-running Slack hobby, finally render cleanly against dark backgrounds.
Second-order effects
- With Microsoft mid-rollout on Outlook and Office dark mode, the two workplace-productivity rivals are now shipping the same checkbox feature within weeks of each other, turning dark mode into table stakes for chat and office suites; apps still without it face the user pressure Sam Sheffer's reaction captures — "great but why'd it take them 5 years?"
Third-order effects
- If the pattern holds, dark mode shifts from launch-worthy headline to permanent maintenance burden: any future interface rework has to ship light and dark variants by default, which is exactly the constraint Slack's own 2020 sidebar redesign would inherit.
The trend: Workplace software vendors are converting dark mode from an OS-level novelty into a default expectation, with Slack and Microsoft normalizing it across chat and office apps in the same season.