Color

#2137e4

#2137e4
hex#2137e4
rgbrgb(33, 55, 228)
hslhsl(233, 78%, 51%)
oklchoklch(0.465 0.254 267.1)
Closest name: Bluebonnet (#1c1cf0)Relative luminance 0.0866

Colors that go with #2137e4

Charcoal, Sea Green 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 →

#e4cd21

#2199e4 · #6b21e4

#e42137 · #37e421

Split-complementary

Open in tool →

#e46b21 · #99e421

#e42199 · #e4cd21 · #21e46b

Contrast

#2137e4 as textRatioAAAA largeAAAFix
Aaon white
7.69:1passpasspassPasses AAA — no fix needed.
Aaon black
2.73:1failfailfail
  • AA: use #5768ea as the text (4.57:1)
  • AAA: use #8491f0 as the text (7.29:1)
  • AA: or shift the background to #c7c7c7 (4.55:1)
  • AAA: or shift the background to #f5f5f5 (7.05:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #2137e4 as the background.

Brands using this color

Fonts for this mood

#2137e4 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #2137e4
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 #2137e4 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/2137e4-9c9cc4-df884e-241f2d-e9eef1?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