DECSET ?2026 — Synchronized update mode

Buffer screen updates until you signal end-of-frame — eliminates flicker on full repaints.

Byte forms

Every common string-literal form so you can paste-and-search either direction.

\\x1b[\x1b[?2026h (begin frame) \x1b[?2026l (end frame)

\\033[\033[?2026h / \033[?2026l

\\e[\e[?2026h / \e[?2026l

ESC [ESC [ ? 2 0 2 6 h / l

hex1b 5b 3f 32 30 32 36 68 / 6c

Description

Originally an iTerm2 + contour proposal, now adopted by kitty, wezterm, foot, ghostty, Windows Terminal, mintty, alacritty (1.7+), and tmux as a pass-through. Wrap a full-screen redraw between `\x1b[?2026h` (begin synchronized update) and `\x1b[?2026l` (end) and the terminal will hold rendering until the `l` arrives, then paint the final state once — eliminating the half-painted frames that plague neovim, helix, tui-rs, ratatui, and similar apps over slow PTYs (especially over SSH). Terminals that don't recognize `?2026` simply paint as bytes arrive, so emitting the pair is safe. Apps that want to detect support should query with the DECRQM request `\x1b[?2026$p` and parse the reply. Recommended max in-frame time is ~100 ms — terminals abort the synchronized state on timeout to avoid a stuck screen.

Spec citation: Synchronized Output Mode (contour spec) / Mode 2026

Examples

bash

printf '\033[?2026h'   # begin frame\n# … emit the full repaint here …\nprintf '\033[?2026l'   # end frame -> painted atomically

python

import sys\nsys.stdout.write('\x1b[?2026h'); redraw(); sys.stdout.write('\x1b[?2026l')

fmt.Print("\x1b[?2026h"); redraw(); fmt.Print("\x1b[?2026l")

javascript

process.stdout.write('\x1b[?2026h'); redraw(); process.stdout.write('\x1b[?2026l')

printf("\x1b[?2026h"); redraw(); printf("\x1b[?2026l");

Terminal support

xterm: no
Linux console (fbcon): no
macOS Terminal.app: no
iTerm2: yes
Windows Terminal: yes
cmd.exe / ConPTY: no
kitty: yes
alacritty: yes
WezTerm: yes
Ghostty: yes
GNOME Terminal: partial
Konsole: yes
tmux: no
GNU screen: no

xterm	Linux console (fbcon)	macOS Terminal.app	iTerm2	Windows Terminal	cmd.exe / ConPTY	kitty	alacritty	WezTerm	Ghostty	GNOME Terminal	Konsole	tmux	GNU screen
no	no	no	yes	yes	no	yes	yes	yes	yes	partial	yes	no	no

Related sequences

In the family cookbook

DEC cookbook · 6. Focus events & sync update — `?1004`, `?2026`