CSS rgba() Color

Web & Network

Validates a CSS rgba(r, g, b, a) color string.

/^rgba$\s*(?:\d{1,3})\s*,\s*(?:\d{1,3})\s*,\s*(?:\d{1,3})\s*,\s*(?:0|1|0?\.\d+)\s*$$/

How it works

Channels are 0–255 (loosely, this pattern accepts up to 3 digits but does not bound numerically). Alpha is 0–1 with an optional decimal. Modern CSS also allows space-separated rgba(r g b / a) which this regex does NOT match.

Test Cases

Should Match

rgba(255, 255, 255, 1)
rgba(0,0,0,0.5)
rgba(128, 64, 32, .75)

Should NOT Match

rgba(255, 255, 255)
rgb(255, 255, 255)
rgba(255 255 255 / 1)

Quick Summary

Matches the comma-separated rgba(r, g, b, a) CSS syntax.