termless

Headless terminal testing library. Like Playwright, but for terminal apps.

Terminal apps are hard to test because the terminal is a black box — you can see text on screen but can't programmatically inspect colors, cursor position, scrollback history, terminal modes, or cell attributes. Termless opens up the entire terminal buffer for structured testing, and runs the same tests against multiple terminal emulators to catch cross-terminal compatibility issues.

Built alongside silvery, a React TUI framework, but works with any terminal app.

• Full terminal internals -- access scrollback, cursor state, cell colors, terminal modes, alt screen, resize behavior — everything that's invisible to string matching
• Cross-terminal conformance -- run the same tests against xterm.js, Ghostty, Alacritty, WezTerm, vt100, and Peekaboo to find where terminals disagree
• Composable region selectors -- term.screen, term.scrollback, term.cell(r, c), term.row(n) for precise assertions
• 21+ Vitest matchers -- text, cell style, cursor, mode, scrollback, and snapshot matchers
• SVG & PNG screenshots -- no Chromium, no native deps (PNG via optional @resvg/resvg-js)
• PTY support -- spawn real processes, send keypresses, wait for output
• Fast -- typically under 1ms per unit-style test (in-memory backend, no PTY). No Chromium, no subprocesses
• CLI + MCP -- termless capture for scripts, termless mcp for AI agents

import { createTerminal } from "@termless/core"
import { createXtermBackend } from "@termless/xtermjs"

const GREEN = (s: string) => `\x1b[38;2;0;255;0m${s}\x1b[0m`

const term = createTerminal({ backend: createXtermBackend(), cols: 80, rows: 24 })
term.feed(GREEN("● API online"))

// String matching sees text. termless sees everything.
term.screen.getText() // "● API online"
term.cell(0, 0).fg // { r: 0, g: 255, b: 0 } — the color getText() can't see

await term.close()