What colors work best for CTA buttons?

The "best" CTA color is the one that contrasts most with its surroundings while remaining on-brand. There's no universally superior color-green doesn't always beat red, orange doesn't always win. Context determines effectiveness.

Color principles: High contrast against the email background. Consistency with brand-the button should feel intentional, not random. Accessibility-sufficient contrast ratio for text readability (WCAG AA minimum). Dark mode consideration-does the color work when inverted?

Test before believing any color "rule." The myth that green converts best or red creates urgency oversimplifies complex psychology. What works depends on your brand context, email design, and audience expectations. A/B test button colors with your actual audience to find what drives clicks for you specifically.