Circuit
Open in tool →Violet plus cyan is the current AI-product signal — pair it with pure black type to keep it from going candy.
Color
#15b3cb
#15b3cb
hex
#15b3cbrgb
rgb(21, 179, 203)hsl
hsl(188, 81%, 44%)oklch
oklch(0.705 0.12 211.9)Closest name: Aquarius (#2db0ce)Relative luminance 0.3671
Colors that go with #15b3cb
Charcoal, Tomato and Denim 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 #15b3cb: softer than #000 and cool enough to feel like part of the same palette.
Tomato #ff6347
complementaryshippedTomato sits directly opposite #15b3cb on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Denim #1560bd
shippedDesigners have shipped Denim with #15b3cb: 7 real palettes, including Coca-Cola's brand system and Venmo's brand system, as the accent.
Dodger Blue #1e90ff
shippedDesigners have shipped Dodger Blue with #15b3cb: 5 real palettes, including Figma's brand system and Patreon's brand system, as the accent.
Midnight Blue #191970
shipped9 real palettes, including Confluent's brand system and Ford's brand system put Midnight Blue beside #15b3cb, as the lead colour.
Orange #ffa500
shipped4 real palettes, including Mistral AI's brand system and Gopro's brand system put Orange beside #15b3cb, as the supporting colour.
Royal Blue #4169e1
shippedRoyal Blue is paired with #15b3cb in 7 real palettes, including Confluent's brand system and Elastic's brand system, as the supporting colour.
Sky Blue #87ceeb
shippedSky Blue is paired with #15b3cb in 4 real palettes, including Max's brand system and Coastal, as the lead colour.
Real palettes that use #15b3cb
Tints & shades
Harmonies
Contrast
| #15b3cb as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 2.52:1 | fail | fail | fail | |
Aaon black | 8.34:1 | pass | pass | pass | Passes 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 #15b3cb as the background.
Brands using this color
Palettes built around it
Deep Water
Open in tool →Cyan and mid-blue on abyss navy with a foam highlight — the ocean at depth; the darker the surface, the brighter the water.
Lagoon
Open in tool →Turquoise and teal with a sand-yellow on white — shallow tropical water; the deep teal text is the reef.
Fonts for this mood
#15b3cb reads as cool, vivid, technical. The font library is tagged with the same vocabulary:
mcpConnect your agent — build around #15b3cb
live endpointPoint 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.
endpoint
https://mcp.brandsweets.com/colors/mcpclaude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt
›analyze #15b3cb and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/15b3cb-a2b7be-df4e81-1f252d-e9f1ee?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