Color

#2129b5

#2129b5
hex#2129b5
rgbrgb(33, 41, 181)
hslhsl(237, 69%, 42%)
oklchoklch(0.394 0.212 269.3)
Closest name: Blue Hour (#0034ab)Relative luminance 0.0525

Colors that go with #2129b5

Charcoal, Steel Blue and 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 →

#b5ae21

#2172b5 · #6421b5

#b52129 · #29b521

Split-complementary

Open in tool →

#b56421 · #72b521

#b52172 · #b5ae21 · #21b564

Contrast

#2129b5 as textRatioAAAA largeAAAFix
Aaon white
10.25:1passpasspassPasses AAA — no fix needed.
Aaon black
2.05:1failfailfail
  • AA: use #646ae3 as the text (4.71:1)
  • AAA: use #8b8fea as the text (7.21:1)
  • AA: or shift the background to #adadad (4.57:1)
  • AAA: or shift the background to #d6d6d6 (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 #2129b5 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

#2129b5 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #2129b5
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 #2129b5 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/2129b5-9f9cc4-df924e-251f2d-e9edf1?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