Terminalizer — Record Terminal Sessions to Animated GIF

Introduction

Terminalizer captures everything happening in your terminal session and replays it as an animated GIF or web-based recording. It is designed for creating documentation, tutorials, and README demos that show terminal workflows in action without requiring viewers to watch a video.

What Terminalizer Does

• Records terminal input and output with precise timing information
• Renders recordings into animated GIF files with customizable quality
• Supports custom frame delays, cursor styles, and terminal themes
• Generates shareable YAML recording files that can be edited before rendering
• Allows sharing recordings via terminalizer.com web player

Architecture Overview

Terminalizer uses node-pty to create a pseudo-terminal that captures all output bytes and timing. The recording is stored as a YAML file containing frame data (content + delay pairs). The render step processes each frame through a headless terminal emulator, captures screenshots as PNG, then assembles them into a GIF using gifencoder with optimized palette quantization.

Self-Hosting & Configuration

• Install globally via npm: npm install -g terminalizer
• Initialize config with terminalizer init to create ~/.terminalizer/config.yml
• Configure output dimensions (cols, rows), GIF quality, and repeat count
• Set custom fonts and themes in the YAML configuration
• Edit recording YAML files to adjust timing or remove frames before rendering

Key Features

• Editable recordings: modify YAML to fix typos or adjust timing post-capture
• Configurable frame delay, quality, and maximum frame count
• Built-in themes and custom color scheme support
• GIF optimization with lossy compression for smaller file sizes
• Web sharing platform for interactive playback without GIF limitations

Comparison with Similar Tools

• asciinema — text-based recording format; lighter but no native GIF export
• VHS (Charm) — script-driven approach; writes commands in a file rather than recording live
• ttyrec/ttygif — older Unix tools; less portable and fewer export options
• Peek — screen recorder for Linux; captures pixels not terminal state

FAQ

Q: How do I reduce the GIF file size? A: Lower the quality setting in config, reduce cols/rows, or use the -q flag during render. Editing the YAML to remove idle frames also helps.

Q: Can I edit the recording after capturing? A: Yes, the recording is a plain YAML file. You can change delays, remove frames, or even modify the displayed text.

Q: What terminal features are supported? A: Full ANSI escape sequences, 256 colors, and Unicode. TrueColor support depends on the renderer.

Q: Can I use custom fonts in the GIF output? A: Yes, specify the font family in the config file. The font must be installed on the rendering machine.

Sources

• https://github.com/faressoft/terminalizer
• https://terminalizer.com