Color

#378fe1

#378fe1
hex#378fe1
rgbrgb(55, 143, 225)
hslhsl(209, 74%, 55%)
oklchoklch(0.637 0.149 250.1)
Closest name: Blue Jay (#5588dd)Relative luminance 0.2589

Colors that go with #378fe1

Charcoal, Crimson and Copper 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 →

#e18937

#37e1de · #373ae1

#e1378f · #8fe137

Split-complementary

Open in tool →

#e1373a · #e1de37

#de37e1 · #e18937 · #3ae137

Contrast

#378fe1 as textRatioAAAA largeAAAFix
Aaon white
3.4:1failpassfail
  • AA: use #1e78cc as the text (4.55:1)
  • AAA: use #175997 as the text (7.21:1)
  • AA: or shift the background to #242424 (4.57:1)
Aaon black
6.18:1passpassfail
  • AAA: use #4e9ce4 as the text (7.2:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #378fe1 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

#378fe1 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #378fe1
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 #378fe1 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/378fe1-9cacc4-df4e4e-1f212d-e9f1f1?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