Color
#5b51db
#5b51dbrgb(91, 81, 219)hsl(244, 66%, 59%)oklch(0.527 0.203 280.1)Colors that go with #5b51db
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.
Charcoal #36454f
neutralshippedCharcoal is the text near-black for #5b51db: softer than #000 and cool enough to feel like part of the same palette.
Sea Green #2e8b57
split-complementshippedSea Green is a split-complement of #5b51db: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Amber #ffbf00
shippedAmber is paired with #5b51db in 6 real palettes, including Mastodon hosted on mastodon.social's brand system and Wikipedia's brand system, as the accent.
Blue #0000ff
shipped10 real palettes, including Signal's brand system and Pixar's brand system put Blue beside #5b51db, as the supporting colour.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #5b51db: 10 real palettes, including NHL's brand system and Warbyparker's brand system, as the accent.
Cornflower Blue #6495ed
shippedDesigners have shipped Cornflower Blue with #5b51db: 8 real palettes, including Mastodon hosted on mastodon.social's brand system and Roblox's brand system, as the supporting colour.
Crimson #dc143c
shippedCrimson is paired with #5b51db in 16 real palettes, including Netflix's brand system and Ulta Beauty's brand system, as the lead colour.
Deep Sky Blue #00bfff
shippedDesigners have shipped Deep Sky Blue with #5b51db: 7 real palettes, including Calm's brand system and Kraken's brand system, as the lead colour.
Real palettes that use #5b51db
Tints & shades
Harmonies
Contrast
| #5b51db as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 5.76:1 | pass | pass | fail |
|
Aaon black | 3.64:1 | fail | pass | fail |
Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #5b51db 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
#5b51db reads as cool, vivid, technical. The font library is tagged with the same vocabulary:
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.
https://mcp.brandsweets.com/colors/mcpclaude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
›analyze #5b51db and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/5b51db-a39cc4-dfa24e-261f2d-e9edf1?lock=0&style=vibrantWant the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.
Machine-readable: color.md