Color

#57b5ef

#57b5ef
hex#57b5ef
rgbrgb(87, 181, 239)
hslhsl(203, 83%, 64%)
oklchoklch(0.74 0.122 238.6)
Closest name: Cerulean (#55aaee)Relative luminance 0.4131

Colors that go with #57b5ef

Charcoal, Dark Orange 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 →

#ef9157

#57efde · #5769ef

#ef57b5 · #b5ef57

Split-complementary

Open in tool →

#ef5769 · #efde57

#de57ef · #ef9157 · #69ef57

Contrast

#57b5ef as textRatioAAAA largeAAAFix
Aaon white
2.27:1failfailfail
  • AA: use #117abb as the text (4.64:1)
  • AAA: use #0d5b8c as the text (7.26:1)
  • AA: or shift the background to #404040 (4.57:1)
  • AAA: or shift the background to #212121 (7.1:1)
Aaon black
9.26:1passpasspassPasses 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 #57b5ef as the background.

Brands using this color

Fonts for this mood

#57b5ef reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #57b5ef
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 #57b5ef and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/57b5ef-9cb0c4-df4e5d-1f222d-e9f1f0?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