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UTF-8 mode
Tests whether the terminal correctly handles UTF-8 encoded text. Virtually all modern terminals default to UTF-8 mode. UTF-8 encodes Unicode code points as 1-4 byte sequences, allowing the full range of Unicode characters (emoji, CJK, mathematical symbols, etc.) to be displayed in the terminal.
How this is testedautomated
Write é (e-acute, 2-byte UTF-8) and 世 (CJK, 3-byte UTF-8), verify each renders as the correct Unicode character.
Write é (e-acute, 2-byte UTF-8) and 世 (CJK, 3-byte UTF-8), verify each renders as the correct Unicode character.
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 Core TUI baseline.
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 |