Twitch Multichat

Combine the chats of several Twitch channels into one view, for collabs, multi-stream events or just your favourite streamers.

Use it at multichat.mnzn.dev or host it yourself. No login needed: chats are read anonymously and read-only.

Usage

Enter one channel per line on the start page and connect, or let "I'm feeling lucky" pick a few trending channels. The channels end up in the URL, so a chat can be bookmarked or shared:

https://multichat.mnzn.dev/-/channel1/channel2/channel3

Settings are stored in the URL as well, e.g. ?size=large&timestamps=true. For OBS and other streaming software, copy the overlay URL from the settings menu and add it as a browser source.

Features

• One merged chat for any number of channels, each message tagged with its channel
• Hide channels by clicking them in the top bar, without leaving the chat
• Emotes from Twitch, BetterTTV and 7TV, including 7TV's stacked (zero-width) emotes. BetterTTV and 7TV emotes update live when a channel changes them, and each service can be turned off
• Moderation: deleted messages, timeouts, bans and cleared chats are removed
• Clickable links
• Stays at the newest message, and stops scrolling while you scroll up to read
• Reconnects after network problems or a sleeping device, and marks the gap in the chat
• Settings: text size, timestamps, channel names, name outlines
• Overlay mode with a transparent background and no top bar, for streaming software
• Installable as an app, updates itself after a new deployment

Self-hosting on NixOS

The flake provides a package and a NixOS module. The app runs with Bun on a unix socket behind nginx, which serves the static files itself. The service needs no network access (it runs without any network interface) and is sandboxed by systemd.

{
  inputs.twitch-multichat.url = "github:meenzen/twitch-multichat";

  outputs = { nixpkgs, twitch-multichat, ... }: {
    nixosConfigurations.server = nixpkgs.lib.nixosSystem {
      modules = [
        twitch-multichat.nixosModules.default
        {
          services.twitch-multichat = {
            enable = true;
            origin = "https://multichat.example.com";
            nginx = {
              enable = true;
              virtualHost = "multichat.example.com";
            };
          };
          # TLS and anything else for the virtual host
          services.nginx.virtualHosts."multichat.example.com" = {
            enableACME = true;
            forceSSL = true;
          };
        }
      ];
    };
  };
}

Without nginx.enable, point your reverse proxy at services.twitch-multichat.socketPath, add its user to services.twitch-multichat.group and set X-Forwarded-Proto and X-Forwarded-Host to your site's fixed scheme and host. Never pass the client's Host on: the app builds link preview URLs from these headers.

Development

Everything runs in the flake's dev shell, which provides Bun and a Chromium for the browser tests:

nix develop -c bun install
nix develop -c bun run dev       # development server
nix develop -c ci                # format, lint, check, test, build, e2e

/dev/chat shows the chat with generated messages, no Twitch connection needed (e.g. /dev/chat?rate=10). The public instance runs on Cloudflare Pages.

See AGENTS.md for the code layout, testing and known pitfalls.