libghostty-vt is a portable, high-performance C library for terminal emulation. It is open source and MIT licensed.

It is highly generic: you give it the bytes a program writes, and it processes and exposes the state of the terminal such as the screen, the cursor, the scrollback, etc.
It is highly portable: we build and test libghostty-vt for Linux, macOS, iOS, Android, FreeBSD, Windows, WebAssembly, and bare-metal RISC-V and ARM. It works on 32-bit and 64-bit systems.
It is high-performance: the IO throughput is best-in-class and faster than any other known terminal emulator. Memory usage is highly optimized, one libghostty-vt consumer was able to run 10,000 active (input/output) terminals with a running shell on a 4 core 8 GB Linux machine.
It has no dependencies: For the highest performance, the library only needs libc, but you can optionally build it without that requirement and it can be fully freestanding on its own and run directly on hardware.

You can use libghostty-vt to build:

Terminal emulators and multiplexers
Web terminals and remote sessions
Session recording and playback
Test harnesses for TUI apps
Agents and automation that read what a TUI is showing
Etc.

libghostty-vt was originally extracted from Ghostty, but since then is in use by hundreds of projects both free and commercial. We don't have any tracking of course but by our best estimates libghostty-vt is used by tens of millions of people daily across every major desktop and mobile platform.

Important: libghostty-vt is pre-1.0. The core code is extremely stable and already in use by millions worldwide, but we're still stabilizing the ABI. We will ship a stable ABI with 1.0 soon. See Stability for exactly what can break.

Where to Next?

Getting the library? See Installing.
Building a terminal? Read Your First Terminal.
Only need one piece? The parsers and encoders work without a terminal. See Building Blocks and Input.
Read API Conventions for general library-wide conventions.

Example

Here is a complete program. It creates a terminal, writes some text with a color sequence in it, and prints what ended up on the screen. We left out the error checks to keep it short.

#include <stdio.h>
#include <string.h>
#include <ghostty/vt.h>
 
int main(void) {
  // Create an 80x24 terminal. NULL selects the default allocator.
  GhosttyTerminal terminal;
  ghostty_terminal_new(NULL, &terminal, 80, 24);
 
  // Write the bytes a program would send. They can come from anywhere: a pty,
  // a network connection, a recording. The escape sequences make "world" bold
  // and green.
  const char *text = "Hello, \x1b[1;32mworld\x1b[0m!\r\n";
  ghostty_terminal_vt_write(terminal, (const uint8_t *)text, strlen(text));
 
  // Read the screen back. A new formatter emits plain text, so the styles
  // don't appear in the output, but you can set options to enable that.
  GhosttyFormatter formatter;
  ghostty_formatter_terminal_new(NULL, &formatter, terminal);
 
  uint8_t *buf = NULL;
  size_t len = 0;
  ghostty_formatter_format_alloc(formatter, NULL, &buf, &len);
  fwrite(buf, 1, len, stdout);
  putchar('\n');
 
  ghostty_free(NULL, buf, len);
  ghostty_formatter_free(formatter);
  ghostty_terminal_free(terminal);
  return 0;
}

Full program: c-vt-hello/src/main.c

It prints Hello, world! in plain text. The color is in the terminal's state but the way we configured the formatter doesn't show it. This has no GUI window and doesn't use a real PTY, but it is hopefully demonstrative of libghostty-vt and how you could hook it up to both.