Synchronized output (DECSET 2026)

Category: modes · Tags: DEC Private Modes · Specification ↗

Synchronized output prevents flicker during screen updates by batching terminal output. The application sends ESC [ ? 2026 h before a render and ESC [ ? 2026 l after. The terminal buffers all output between these markers and renders it as a single atomic frame. Without synchronized output, complex TUI updates (clearing screen, repositioning cursor, writing content) may partially render between frames, causing visible tearing or flicker. This is especially noticeable over slow connections or with complex layouts. This protocol was proposed by the terminal-wg (Terminal Working Group) and adopted by Ghostty, Kitty, WezTerm, foot, Contour, and other modern terminals. It has become the standard way to achieve flicker-free TUI rendering.

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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