KaraFlow

A real-time karaoke platform for venues and home parties: guests queue songs from their phones, a TV player follows along live, and pricing scales from a free home room to a venue subscription.

Category: Product & UX
Year: 2026
Role: Product, UX, business model and build
Stack: Next.js 15 (App Router) · Tailwind CSS v4 · Supabase (Postgres, Auth, Realtime, RLS) · YouTube · Vimeo · Dailymotion · Android TV · Tizen · webOS · Cursor agents

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Problem

At a karaoke night the queue usually lives on paper slips or in the host's head. Guests don't know when it's their turn, the host juggles requests while searching for videos, and nobody can change the key for a singer without stopping the show.

Approach

I split the experience into three connected surfaces, one per role:

- **Host**: venues run each night from a dashboard and controller; at home, the person who created the room controls it straight from the TV player.

- **Guests**: they scan a QR code or type a room code, enter a name and start queuing, with no account and nothing to install. Songs come from a shared catalogue or from a pasted YouTube, Vimeo or Dailymotion link.

- **TV player**: a full-screen page that follows the room live through Supabase Realtime. In home rooms, playback starts by itself as soon as the first song is queued. A TV interface with on-screen keyboard and remote control, plus app wrappers for Android TV, Samsung Tizen and LG webOS, bring it to smart TVs.

Embedded video players can’t change the key of a song, so I also built a browser extension for Chrome and other Chromium browsers. Running on the player, it reads the pitch set for the room and shifts the audio live. In autoplay mode the control appears on the singer’s own phone; in manual mode it stays with the host.

YouTube is the main path, with the catalogue, pitch control and automatic next-song. Vimeo and Dailymotion are supported through embeds, with a small API that reads metadata from any of the three providers.

Rules live on the server. Device caps, songs per person and bans are enforced by Postgres functions and Row Level Security, so nobody can bypass them from the browser, and only venue accounts can create venue rooms. Home rooms are deleted permanently when closed.

Result

The platform is live and the home tier is open to anyone. For venues, I'm currently in talks with a few trusted local bars to run the first pilot nights, which will set the Business pricing and the next round of features.

Plans

Plan	Who it's for	Devices	Songs per device	Pitch control	Price
Free	Karaoke at home	5	1	—	Free
Pro	A bigger party	15	10	—	€1.99 for 24 hours
Business	Bars and venues	Unlimited	Configurable	Yes	[€ / month]

A Pro pass can be handed over to another account in the same room, so the night keeps going if the person who started it leaves early. Next idea under evaluation: packs of 10 Pro passes for €15 instead of €20.

Design decisions

One surface per role. Host, guests and TV each get only what they need, so nobody has to share a device.
Join in seconds. A QR code and a name are enough; asking guests to sign up at a party would kill participation.
From venues to living rooms. Home rooms need no dashboard: create, open the TV, queue from the phone and autoplay does the rest.
Pricing that follows real use. Venues sing every week and pay monthly; friends sing once in a while and pay only for the night they need.
Trust the server, not the client. Limits, bans and room permissions run in the database, so the rules hold even if someone tampers with the page.
Work around the platform, not against it. When the video players couldn’t change pitch, a small browser extension added the feature without leaving the embeds people already know.
Graceful degradation. Every provider plays; YouTube gets the full feature set, and the others get the essentials instead of nothing.
Small, reviewable steps. The product grew through 30+ database migrations and pull requests opened by Cursor's background agents, each with deploy notes and a test checklist, which I reviewed and shipped.

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