Color

#3ff31b

#3ff31b
hex#3ff31b
rgbrgb(63, 243, 27)
hslhsl(110, 90%, 53%)
oklchoklch(0.842 0.272 141.3)
Closest name: Becquerel (#4bec13)Relative luminance 0.6524

Colors that go with #3ff31b

Deep Sky Blue, Violet and Hot Pink 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 →

#cf1bf3

#abf31b · #1bf363

#1b3ff3 · #f31b3f

Split-complementary

Open in tool →

#631bf3 · #f31bab

#1babf3 · #cf1bf3 · #f3631b

Contrast

#3ff31b as textRatioAAAA largeAAAFix
Aaon white
1.49:1failfailfail
  • AA: use #1d8807 as the text (4.59:1)
  • AAA: use #156605 as the text (7.16:1)
  • AA: or shift the background to #595959 (4.69:1)
  • AAA: or shift the background to #3d3d3d (7.27:1)
Aaon black
14.05:1passpasspassPasses 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 #3ff31b 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 #3ff31b
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 #3ff31b and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3ff31b-a3bea2-814edf-1f2d23-eef1e9?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