#21d439 as text	Ratio	AA	AA large	AAA	Fix
Aaon white	1.99:1	fail	fail	fail	AA: use #158925 as the text (4.53:1) AAA: use #10651b as the text (7.24:1) AA: or shift the background to #474747 (4.66:1) AAA: or shift the background to #2b2b2b (7.11:1)
Aaon black	10.54:1	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 #21d439 as the background.

Brands using this color

No public brand in the corpus uses this exact color yet. Extract a brand to add one.

mcpConnect your agent — build around #21d439

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 #21d439 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/21d439-a2bea9-ac4edf-1f2d27-ecf1e9?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