Color

#ef0101

#ef0101
hex#ef0101
rgbrgb(239, 1, 1)
hslhsl(0, 99%, 47%)
oklchoklch(0.598 0.245 29.2)
Closest name: Alarm (#ec0003)Relative luminance 0.1837

Tints & shades

Every swatch is its own page — click any to analyze it.

Harmonies

Complementary

Open in tool →

#01efef

#ef0178 · #ef7801

#01ef01 · #0101ef

Split-complementary

Open in tool →

#01ef78 · #0178ef

#78ef01 · #01efef · #7801ef

Contrast

#ef0101 as textRatioAAAA largeAAAFix
Aaon white
4.49:1failpassfail
  • AA: use #e90101 as the text (4.7:1)
  • AAA: use #b20101 as the text (7.25:1)
  • AA: or shift the background to #050505 (4.54:1)
Aaon black
4.67:1passpassfail
  • AAA: use #fe6262 as the text (7.14:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #ef0101 as the background.

Brands using this color

Fonts for this mood

#ef0101 reads as warm, vivid, playful. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #ef0101
live endpoint

Point any MCP client at the shared colors endpoint and your agent gets the same engine as this page — generate_palette, check_contrast, analyze_color — read-only, no key. Every palette it proposes comes with a /palettes/new/… link: open it, lock what you like, paste the link back.

endpointhttps://mcp.brandsweets.com/colors/mcp
claude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt

analyze #ef0101 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/ef0101-c4a19c-62cb98-2d251f-f1e9ed?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