KAPOW! vs Karaoke Eternal

Two different nights

Both projects run a karaoke queue that guests join from their phones. The difference is where the songs come from, and it decides almost everything else.

Karaoke Eternal plays a library you own. MP3+G, MP4, sitting on your disk. Everything is local, so it works with the router unplugged, and there is no quota, no API key and no external service.

KAPOW! searches YouTube. There is no library to build, and a guest can request essentially any song that exists. In exchange it needs internet, a YouTube Data API key and a Supabase project.

If you already own karaoke files, that is an investment Karaoke Eternal honours and KAPOW! does not. If you do not, building one is a real project before your first night.

Why KAPOW! exists

It was written for a comic-themed bar in Ghent that was managing its karaoke queue with coasters.

That setting explains the design choices. In a bar, guests are strangers, they are not installing anything, and the failure mode that ends a night is somebody asking for a song you do not have. A curated local library makes that failure mode routine; YouTube search makes it rare.

It also explains the three separate surfaces. Guests get search and voting on their phones. The host gets a booth view with direct queue control — promote, reorder, drop. The TV gets its own full-screen route. Those are different jobs for different people, so they are different routes rather than one interface with permission checks.

Voting

Karaoke Eternal’s queue is host-managed with per-singer rotation, which is fair and predictable: everyone gets a turn in order.

KAPOW! adds crowd voting. Guests vote on pending songs and the popular ones rise. The host still decides — voting shapes order rather than dictating it — but the room has a say.

Which you want is genuinely a matter of venue. Rotation is fairer and better for a small group where everybody wants to sing. Voting is better with a large crowd where most people are watching rather than performing, because it surfaces what the room wants to hear.

The dependency question

This is where KAPOW! departs from Coral’s own stated principles, and it is worth being direct about it rather than glossing over it.

Every other Coral module runs with no cloud dependency, keeps state in local SQLite, and needs no internet. KAPOW! needs hosted Supabase for realtime room state and the YouTube API for search.

The Supabase part is defensible on technical grounds. A karaoke room is a realtime multi-device problem — thirty phones, a host tablet and a TV need the same queue within a second — and local SQLite with polling degrades exactly when the room is full. The YouTube part is inherent to sourcing songs from YouTube.

But the consequence is real: a venue with flaky internet should run Karaoke Eternal. There is no workaround.

Other options worth knowing

The self-hosted karaoke space is small, so the honest comparison is not just these two.

Karaoke Eternal — local library, browser-based playback for MP3+G and MP4, WebGL visualisations. The mature default.

KaraokeParty — local library, QR-code join, runs on a Pi or Mac mini. Closest in spirit to KAPOW! on the guest-experience side while staying fully local.

Nightingale — different problem entirely. It scans a Jellyfin server, separates vocals from instrumentals with an AI model, transcribes word-level lyrics, and does pitch scoring. If you want scoring, neither KAPOW! nor Karaoke Eternal does that and Nightingale does.

karaoke-for-jellyfin — plays karaoke tracks already in your Jellyfin library, with phone queueing and a TV view. The best fit if your karaoke files are already catalogued in Jellyfin.

Trying KAPOW!

Two external accounts before you start: a Supabase project, and a YouTube Data API key.

services:
  kapow:
    image: getcoral/kapow:latest
    restart: unless-stopped
    ports:
      - "3000:3000"
    environment:
      SUPABASE_URL: ${SUPABASE_URL}
      SUPABASE_PUBLISHABLE_KEY: ${SUPABASE_PUBLISHABLE_KEY}
      SUPABASE_DB_PASSWORD: ${SUPABASE_DB_PASSWORD}
      YOUTUBE_API_KEY: ${YOUTUBE_API_KEY}

Full setup is on the KAPOW! module page. If what you actually want is moderated music requests rather than karaoke — guests suggesting tracks from your own Jellyfin library, host approving — that is Encore and it is a different module.