Slack Green

Slack theme generator

Make a custom Slack theme from 4 colors, a logo, or one of Slack's 34 themes, and see it the way Slack will draw it. The preview runs Slack's own color rules, so it shows what Import really does: light sidebars with unreadable channel names, Darker sidebars, and the gradient Import turns off.

Search Acme
A
Home
DMs
2Activity
Files
Acme
Channels
# general
# design-review2
# launch
# old-project
Direct messages
Priya
Sam
# launch
Priya 10:24
Theme is live for the launch week.
Sam 10:24
Channel names still readable on my side.
The same settings Slack has
Color mode
Selected before Import
  • Channel names on the sidebar6.72:1
  • Unread channels (bold)9.94:1
  • Text on the selected channel17.54:1
  • Rail and top bar labels13.62:1
  • Mention badge number4.80:1
#14532D,#DCFCE7,#22C55E,#C2410C
  1. In Slack, click your profile picture, then Preferences, then Appearance.
  2. Under Slack themes, click Aubergine first. Slack keeps the brightness of the theme you had selected, and Aubergine is the one that lets you choose Darker sidebars.
  3. Open Custom theme, click Import, paste the string and click Apply.
  4. Darker sidebars: leave it ticked.
  5. Leave Window gradient unticked (Import unticks it).
  6. Close Preferences and click Save Changes. Until then Slack only previews the theme, and Undo changes puts the old one back.

Colors come from Slack's own theme code, checked against real imports in Slack for web on 8 October 2026.

How to make a custom Slack theme

  1. Pick the 4 colors: System navigation (window and sidebar), Selected items, Presence indication and Notifications. Or take them from a logo, from one of Slack's themes, or from a theme string someone shared.
  2. Set Color mode, Darker sidebars and Window gradient the way you use Slack, and read the checks under the preview. Each one is a contrast ratio on the colors Slack draws.
  3. Click Copy theme. In Slack open Preferences, then Appearance. Click Aubergine under Slack themes first, then open Custom theme, click Import, paste and click Apply.
  4. Set Darker sidebars as the preview shows, and tick Window gradient again if you want it. Import always unticks it. Close Preferences and click Save Changes, or Slack drops the theme.

Frequently asked questions

Why are my channel names unreadable after importing a Slack theme?

Darker sidebars was on. Slack keeps the brightness of the theme you had selected, so after Aubergine every import gets Darker sidebars, even a light one. In our test on 8 October 2026, #E7E5E4 as System navigation gave a sidebar of rgb(233, 231, 230) with channel names in rgb(231, 229, 228), a contrast of 1.02:1. Untick Darker sidebars under Custom theme and the text turns dark.

How many colors does a Slack theme string need?

4, 8 or 10 hex colors with #, separated by commas; spaces and lowercase are fine. Slack uses 4 of them: with 8 or 10 it keeps colors 1, 3, 7 and 8. Anything else, Slack's own Share sentence ('Check out my Slack theme: ...') included, gets 'Invalid theme string'. Paste it here and the tool gives you the 4 colors to use.

Why did my Slack theme come out with a white sidebar?

The theme selected before Import was a light one such as Banana. Then Slack hides Darker sidebars and draws a near-white sidebar, and your System navigation color shows only in the top bar and the rail. Click Aubergine under Slack themes, import again, and Darker sidebars comes back.

What are the Miles Davis Slack theme colors?

Kind of Blue #4C64A6,#71A3D1,#14ADFF,#1D3F5E; Funky Fresh #BEB0FF,#71D18F,#00FF50,#CDC8E8; Jazz Club #9C0000,#070C52,#000261,#026B5A; Electric Fusion #DCF095,#ADFFBC,#C674F2,#C674F2; Brassy #FAD961,#F0E6C2,#EDCE34,#ACDFE3; Sunglasses Inside #2B102E,#D1B4E0,#41B584,#C494D6. These are the values in Slack's code; pick one under Slack's themes here to preview or tweak it.

Why does the selected channel text change between dark and light?

Slack picks it for you. It turns each color into 12 shades and uses dark text on a Selected items color whose lightness (HCT tone) is 66 or more, light text below that. The same rule sets the number color on mention badges. You cannot choose the text color.

Related reading

Slack Green does one thing: it keeps your Slack presence dot green while you are actually working, so a quiet keyboard does not mark you away. Try it free.