Color

#421cd9

#421cd9
hex#421cd9
rgbrgb(66, 28, 217)
hslhsl(252, 77%, 48%)
oklchoklch(0.442 0.253 277.4)
Closest name: Busty Blue (#3300cc)Relative luminance 0.07

Colors that go with #421cd9

Charcoal, Cobalt Blue and Cornflower Blue 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 →

#b3d91c

#1c55d9 · #a01cd9

#d9421c · #1cd942

Split-complementary

Open in tool →

#d9a01c · #55d91c

#d91c55 · #b3d91c · #1cd9a0

Contrast

#421cd9 as textRatioAAAA largeAAAFix
Aaon white
8.75:1passpasspassPasses AAA — no fix needed.
Aaon black
2.4:1failfailfail
  • AA: use #795dea as the text (4.57:1)
  • AAA: use #9e8af0 as the text (7.35:1)
  • AA: or shift the background to #bababa (4.51:1)
  • AAA: or shift the background to #e6e6e6 (7.01:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #421cd9 as the background.

Brands using this color

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

Fonts for this mood

#421cd9 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #421cd9
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 #421cd9 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/421cd9-a99cc4-dfb64e-281f2d-e9ecf1?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