Never Punch Manticores


    3.0.0-beta.4 • Public • Published

    Note: This README applies to development branch. See the version for the latest stable release here.

    asciinema player

    Build status

    Web player for terminal session recordings (as produced by asciinema recorder) that you can use on your own website.


    asciinema player is an open-source terminal session player written in Javascript and Rust/WASM. Unlike other video players asciinema player doesn't play heavy-weight video files (.mp4, .webm etc) and instead plays light-weight terminal session files called asciicasts.

    Asciicast is a capture of terminal's raw output, which has to be interpreted during the playback, so the player comes with its own interpreter based on Paul Williams' parser for ANSI-compatible video terminals. Its output is fully compatible with most widely used terminal emulators like xterm, Gnome Terminal, iTerm etc.

    You can see the player in action on

    If you don't want to depend on and you prefer to host the player and the recordings yourself then read on, it's very simple.


    Quick start

    The following examples show how to use asciinema player on your own website, without depending on

    It assumes you have obtained terminal session recording file by either:

    Use the standalone player bundle in your HTML page

    Download latest version of the player bundle from releases page. You only need asciinema-player.min.js and asciinema-player.css files.

    First, add asciinema-player.min.js, asciinema-player.cssand the .cast file of your recording to your site's assets. The HTML snippet below assumes they're in the web server's root directory.

    Then add necessary includes to your HTML document and initialize the player inside an empty <div> element:

      <link rel="stylesheet" type="text/css" href="/asciinema-player.css" />
      <div id="demo"></div>
      <script src="/asciinema-player.min.js"></script>
        AsciinemaPlayer.create('/demo.cast', document.getElementById('demo));

    Use the player in your own application bundle

    Add asciinema-player to your devDependencies:

    npm install --save-dev asciinema-player@3.0.0-beta.3

    Add empty <div id="demo"></div> element to your page to contain the player.

    Import and use create function from asciinema-player module:

    import * as AsciinemaPlayer from 'asciinema-player';
    AsciinemaPlayer.create('/demo.cast', document.getElementById('demo'));

    Finally, include player's CSS file - found in the npm package at dist/bundle/asciinema-player.css - in your CSS bundle.


    To mount the player in your page call the create function exported by the asciinema-player ES module with 2 arguments: the URL (or path) to the asciicast file and the container DOM element to mount the player in.

    const player = AsciinemaPlayer.create(url, containerElement);

    The returned object contains the following attributes:

    • el - DOM element of the player
    • dispose - a function to dispose the player, i.e. to remove it from the page

    To pass additional options when mounting the player use 3 argument variant:

    const player = AsciinemaPlayer.create(url, containerElement, opts);

    For example, to enable looping and select Solarized Dark theme:

    AsciinemaPlayer.create('/demo.cast', document.getElementById('demo'), {
      loop: true,
      theme: 'solarized-dark'

    See below for a full list of available options.


    Type: number

    Number of columns of player's terminal.

    When not set it defaults to 80 (until asciicast gets loaded) and to terminal width saved in the asciicast file (after it gets loaded).

    It's recommended to set it to the same value as in asciicast file to prevent player to resize itself from 80x24 to the actual dimensions of the asciicast when it gets loaded.


    Type: number

    Number of lines of player's terminal.

    When not set it defaults to 24 (until asciicast gets loaded) and to terminal height saved in the asciicast file (after it gets loaded).

    Same recommendation as for cols applies here.


    Type: boolean

    Set this option to true if playback should start automatically.

    Defaults to false - no auto play.


    Type: boolean

    Set this option to true if the recording should be preloaded on player's initialization.

    Defaults to false - no preload.


    Type: boolean or number

    Set this option to either true or a number if playback should be looped. When set to a number (e.g. 3) then the recording will be re-played given number of times and stopped after that.

    Defaults to false - no looping.


    Type: number or string

    Start playback at a given time.

    Supported formats:

    • 123 (number of seconds)
    • "2:03" ("mm:ss")
    • "1:02:03" ("hh:mm:ss")

    Defaults to 0.


    Type: number

    Playback speed. The value of 2 means 2x faster.

    Defaults to 1 - normal speed.


    Type: number

    Limit terminal inactivity to a given number of seconds.

    For example, when set to 2 any inactivity longer than 2 seconds will be "compressed" to 2 seconds.

    Defaults to:

    • idle_time_limit from asciicast header (saved when passing -i <sec> to asciinema rec),
    • no limit, when it was not specified at the time of recording.


    Type: string

    Terminal color theme.

    One of:

    • "asciinema"
    • "monokai"
    • "tango"
    • "solarized-dark"
    • "solarized-light"

    Defaults to "asciinema".

    You can also use a custom theme.


    Type: string

    Poster (a preview frame) to display until the playback is started.

    The following poster specifications are supported:

    The easiest way of specifying a poster is to use NPT format. For example, npt:1:23 will preload the recording and display terminal contents at 1 min 23 sec.


      src: '/demo.cast',
      poster: 'npt:1:23'
    }, document.getElementById('demo'));

    Alternatively, a poster value of data:text/plain,This will be printed as poster\n\rThis in second line will display arbitrary text. All ANSI escape codes can be used to add color and move the cursor around to produce good looking poster.

    Example of using custom text poster with control sequences (aka escape codes):

      src: '/demo.cast',
      poster: "data:text/plain,I'm regular \x1b[1;32mI'm bold green\x1b[3BI'm 3 lines down"
    }, document.getElementById('demo'));

    Defaults to blank terminal or, when startAt is specified, to screen contents at time specified by startAt.


    Type: string

    Controls the player's fitting (sizing) behaviour inside its container element.

    Possible values:

    • "width" - scale to full width of the container
    • "height" - scale to full height of the container (requires the container element to have fixed height)
    • "both" - scale to either full width or height, maximizing usage of available space (requires the container element to have fixed height)
    • false / "none" - don't scale, use fixed size font (also see fontSize option below)

    Defaults to "width".

    Version 2.x of the player supported only the behaviour represented by the false value. If you're upgrading from v2 to v3 and want to preserve the sizing behaviour then include fit: false option.


    Type: string

    Size of the terminal font.

    Possible values:

    • "small"
    • "medium"
    • "big"
    • any valid CSS font-size value (e.g. "15px")

    Defaults to "small".

    This option is effective only when fit: false option is specified as well (see above).

    Keyboard shortcuts

    The following keyboard shortcuts are currently available (when the player element is focused):

    • space - play / pause
    • f - toggle fullscreen mode
    • / - rewind 5 seconds / fast-forward 5 seconds
    • 0, 1, 2 ... 9 - jump to 0%, 10%, 20% ... 90%


    The project requires Node.js, npm and Rust for development and build related tasks so make sure you have the latest versions installed.

    To build the project:

    git clone
    cd asciinema-player
    git submodule update --init
    npm install
    npm run build
    npm run bundle

    This produces:

    • dist/index.js - ES module, to be import-ed in your JS bundle
    • dist/bundle/asciinema-player.js - standalone player script, to be linked directly from a website
    • dist/bundle/asciinema-player.min.js - minimized version of the above
    • dist/bundle/asciinema-player.css - stylesheet, to be linked directly from a website or included in a CSS bundle


    If you want to contribute to this project check out Contributing page.


    Developed with passion by Marcin Kulik and great open source contributors.


    Copyright © 2011-2021 Marcin Kulik.

    All code is licensed under the Apache License, Version 2.0. See LICENSE file for details.




    npm i asciinema-player@3.0.0-beta.4





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