24-bit truecolor

Category: extensions · Tags: Xterm Extensions · Specification ↗

24-bit truecolor allows terminals to display any of 16.7 million colors (256 values per R/G/B channel), far beyond the 256-color palette. The escape sequences are ESC [ 38 ; 2 ; R ; G ; B m for foreground and ESC [ 48 ; 2 ; R ; G ; B m for background. There are two syntax variants: the original semicolon-separated format (38;2;R;G;B) introduced by xterm, and the colon-separated format (38:2::R:G:B) defined by ITU T.416. The colon format is technically more correct and avoids parsing ambiguities, but the semicolon format has wider support. Applications should use the semicolon variant for maximum compatibility. Applications can detect truecolor support via the COLORTERM=truecolor environment variable. Nearly all modern terminals support 24-bit color; the main exceptions are older versions of macOS Terminal.app and some minimal terminal emulators.

Supported by 6 of 6 backends (100%)

Support Matrix

Backend	Version	Support	Notes
Alacritty	0.26.0	✓ yes
Ghostty	1.3.1	✓ yes
Kitty	0.40.0	✓ yes
vt100	0.1.0	✓ yes
WezTerm	0.1.0-fork.5	✓ yes
xterm.js	5.5.0	✓ yes

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