Color

#66e577

#66e577
hex#66e577
rgbrgb(102, 229, 119)
hslhsl(128, 71%, 65%)
oklchoklch(0.825 0.188 146.2)
Closest name: Grotesque Green (#64e986)Relative luminance 0.602

Colors that go with #66e577

Charcoal, Deep Sky Blue and Taupe 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 →

#e566d4

#95e566 · #66e5b7

#7766e5 · #e57766

Split-complementary

Open in tool →

#b766e5 · #e56695

#6695e5 · #e566d4 · #e5b766

Contrast

#66e577 as textRatioAAAA largeAAAFix
Aaon white
1.61:1failfailfail
  • AA: use #178726 as the text (4.64:1)
  • AAA: use #11641c as the text (7.33:1)
  • AA: or shift the background to #545454 (4.7:1)
  • AAA: or shift the background to #383838 (7.28:1)
Aaon black
13.04:1passpasspassPasses 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 #66e577 as the background.

Brands using this color

mcpConnect your agent — build around #66e577
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 #66e577 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/66e577-a2bea9-ac4edf-1f2d27-ecf1e9?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