Color

#21e41b

#21e41b
hex#21e41b
rgbrgb(33, 228, 27)
hslhsl(118, 79%, 50%)
oklchoklch(0.799 0.264 142.4)
Closest name: Alarming Slime (#2ce335)Relative luminance 0.5589

Colors that go with #21e41b

Deep Sky Blue, Taupe and Violet lead the list. Each partner is a real named colour with the reason it works — a wheel relationship, a neutral that carries it, or a pairing lifted from a palette or brand system that actually shipped — and every pair opens in the palette tool.

Tints & shades

Every swatch is its own page — click any to analyze it.

Harmonies

Complementary

Open in tool →

#de1be4

#86e41b · #1be479

#1b21e4 · #e41b21

Split-complementary

Open in tool →

#791be4 · #e41b86

#1b86e4 · #de1be4 · #e4791b

Contrast

#21e41b as textRatioAAAA largeAAAFix
Aaon white
1.72:1failfailfail
  • AA: use #148910 as the text (4.55:1)
  • AAA: use #0f640c as the text (7.37:1)
  • AA: or shift the background to #525252 (4.53:1)
  • AAA: or shift the background to #363636 (7.01:1)
Aaon black
12.18:1passpasspassPasses AAA — no fix needed.

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #21e41b as the background.

Brands using this color

No public brand in the corpus uses this exact color yet. Extract a brand to add one.

mcpConnect your agent — build around #21e41b
live endpoint

Point any MCP client at the shared colors endpoint and your agent gets the same engine as this page — direct_palette, edit_direction, check_palette, check_contrast — read-only, no key. Every direction it proposes comes with a /colors/d/… link: open it, lock what you like, paste the link back, and the agent edits rather than re-rolls.

endpointhttps://mcp.brandsweets.com/colors/mcp
claude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt

analyze #21e41b and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/21e41b-a2bea4-944edf-1f2d25-edf1e9?lock=0&style=vibrant

Want the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.

Machine-readable: color.md