Asciinema

Asciinema is a terminal session recorder and player that captures what happens in your shell and replays it as a text-based “asciicast”. It is commonly used to share CLI demos, tutorials, and bug reproductions with accurate timing and copyable output.

Key Features

• Records terminal input/output with timing data (not a video), producing small .cast files
• Local playback in the terminal via asciinema play
• Web playback via an embeddable HTML player (asciinema player)
• Upload/sharing workflow using asciinema upload and the asciinema.org hosting service (optional)
• Copyable terminal text during playback (useful for commands/snippets)
• JSON-based cast format that can be post-processed and integrated into toolchains
• Supports theming and terminal size metadata for consistent replays

Use Cases

• Create CLI demos for README files, documentation portals, and blog posts
• Share reproducible bug reports or support requests with exact terminal timing
• Produce training materials for internal tooling and onboarding

Limitations and Considerations

• Captures terminal I/O, not pixels: full-screen TUIs may replay differently across environments
• Not suitable for demos requiring rich visuals (images/video); use screen recording for that

Asciinema provides a practical middle ground between static snippets and heavyweight video recordings, enabling accurate, lightweight, and script-friendly sharing of terminal sessions. It fits well into developer documentation and teaching workflows where copyable output and small artifacts matter.