Features›SGR (Text Styling)›24-bit fg (SGR 38;2)

24-bit fg (SGR 38;2)

Category: sgr · Baseline: modern · Tags: Xterm Extensions · Specification ↗

ESC [ 38;2;R;G;B m

SGR 38;2;R;G;B sets the foreground to a 24-bit RGB color. The sequence is ESC [ 38;2;R;G;B m where R, G, B are 0-255. There is also a colon-separated variant ESC [ 38:2::R:G:B m per ITU T.416, but the semicolon format has wider compatibility. This gives applications access to 16.7 million colors. Applications can check for truecolor support via COLORTERM=truecolor or COLORTERM=24bit in the environment.

How this is testedautomated
Send \x1b[38;2;255;128;0mX, verify the foreground color matches RGB(255, 128, 0) exactly.

The same probe runs against headless backends (via Termless) and real terminal apps (via a daemon launched in each terminal). This lets us distinguish parser correctness from rendering correctness.

Analysis2026-04-06

Supported by 11 of 12 terminals (92%). Not supported by: vt100.js. Part of the Modern TUI baseline. Notes: vt100.js: Not in VT100/VT220 — only 8 standard colors supported.

Supported by 13 of 14 backends (93%)

Terminal Applications

Terminal	Version	Support	Notes
iTerm2	3.6.9	✓ yes
Ghostty	1.3.1	✓ yes
VS Code		✓ yes
Warp		✓ yes
Cursor		✓ yes
Terminal.app		✓ yes

Headless Backends

Parser correctness only — a ✓ means the parser accepts the sequence.

Backend	Version	Support	Notes
Alacritty	0.26.0	✓ yes
Kitty	0.40.0	✓ yes
vterm	0.2.0	✓ yes
WezTerm	0.1.0-fork.5	✓ yes
xterm.js	5.5.0	✓ yes
vt100.js	0.2.1	✗ no	Not in VT100/VT220 — only 8 standard colors supported

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