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Blink (SGR 5)
ESC [ 5 mSGR 5 causes text to blink at a steady rate. The sequence is
ESC [ 5 m. Many modern terminals intentionally do not implement blinking, as it is considered distracting and an accessibility concern. Terminals that do support it typically allow the user to disable it in preferences.How this is testedautomated
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Send
\x1b[5mX, verify blink=true on the cell.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 all 12 tested terminals — universal adoption. Part of the Modern TUI baseline.
Supported by 11 of 14 backends (79%)
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 |
|---|---|---|---|
| Kitty | 0.40.0 | ✓ yes | |
| vt100.js | 0.2.1 | ✓ yes | |
| vterm | 0.2.0 | ✓ yes | |
| Alacritty | 0.26.0 | ~ partial | Not exposed via alacritty_terminal API |
| WezTerm | 0.1.0-fork.5 | ~ partial | Not exposed via wezterm-term API |
| xterm.js | 5.5.0 | ~ partial | Parser handles SGR 5 but headless mode doesn't expose blink attribute |