Color

#2551ef

#2551ef
hex#2551ef
rgbrgb(37, 81, 239)
hslhsl(227, 86%, 54%)
oklchoklch(0.517 0.24 265.6)
Closest name: Blue Ribbon (#0066ff)Relative luminance 0.1251

Colors that go with #2551ef

Charcoal, Crimson and Amber 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 →

#efc325

#25b5ef · #5e25ef

#ef2551 · #51ef25

Split-complementary

Open in tool →

#ef5e25 · #b5ef25

#ef25b5 · #efc325 · #25ef5e

Contrast

#2551ef as textRatioAAAA largeAAAFix
Aaon white
6:1passpassfail
  • AAA: use #1140e8 as the text (7.19:1)
Aaon black
3.5:1failpassfail
  • AA: use #466bf1 as the text (4.63:1)
  • AAA: use #7591f5 as the text (7.13:1)
  • AA: or shift the background to #e0e0e0 (4.54:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #2551ef as the background.

Brands using this color

Fonts for this mood

#2551ef reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #2551ef
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 #2551ef and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/2551ef-9ca0c4-df7a4e-221f2d-e9eff1?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