PrimeTime Trivia

A pub trivia system built for a real weekly game night.

Every Thursday a room of people plays trivia on their own phones while the questions run on a television. There is no app to install and nothing on anyone's phone but a web page. The MC runs the whole night from a phone in their hand.

I wrote it because the commercial options all assumed something that was not true of this room: reliable internet, a venue that would let devices talk to each other, or a host willing to stand at a laptop all evening. What follows is one question, from a player tapping join to the scores going up, screen by screen.

One question, five screens

Joining

A player opens the address on the big screen and lands here. The choice matters more than it looks: a couple sharing one phone should be one entry, not two, and four people at a table who each brought a phone usually want to be one team. Asking once, in plain words, removes an argument later.

A phone screen headed Welcome, reading 'One device per entry. Play on your own, or share this device with the people at your table.' with two buttons, 'Just me' and 'A team on this device', above the room code PALM-6. — The room code sits at the bottom of every player screen, because the question people ask their neighbour is always **“what room are we in?”**

The question, in two places at once

The same question renders on the television and in every hand. The TV carries the things a room reads together: the category, the clock, the points, who is winning. The phone carries only what you tap.

A television screen showing the category Radio and Comedy, a 1000 points and 19 seconds badge, the question 'What is a laugh track?', four lettered answers, a live standings panel on the right, and a counter reading 0 of 4 in. — Look at the answer badges. **A is a circle, B a square, C a diamond, D a shield.** Colour alone would fail the eight percent of men with colour vision deficiency, and in a dim room with a projector it fails almost everybody, so the shape carries the meaning and the colour is decoration. The counter under the answers shows how many have come in, never who answered what.

The same question on a phone, with the four answers stacked as large tap targets and the prompt 'Tap your answer.' — Look at the answer badges. **A is a circle, B a square, C a diamond, D a shield.** Colour alone would fail the eight percent of men with colour vision deficiency, and in a dim room with a projector it fails almost everybody, so the shape carries the meaning and the colour is decoration. The counter under the answers shows how many have come in, never who answered what.

What the MC sees

This is the screen that decides whether a night runs well, and it is the one nobody designs. The answer and the fact to read aloud are here, on the host's phone, and nowhere else until the reveal.

An MC control screen on a phone showing a Live badge, a 19 second timer, the question, the correct answer C highlighted in green with the explanatory fact beneath it, and buttons for plus 15 seconds, Lock now, Skip, Pause and Answers in. — **+15s** and **Lock now** exist because a real room is not on a schedule. A table is still arguing, or everyone finished in nine seconds and the clock is dead air. The MC adjusts rather than waiting out a timer somebody else chose.

The reveal

The correct answer lights up, the wrong ones drain of colour, and the room gets told why.

Between questions

Standings, and a countdown so the room knows whether there is time to go to the bar.

Where the questions come from

The bank holds just under two thousand questions across several decks, and the hard part was never writing them. It was writing ones that are true. An authoring tool drafts questions against a category and a difficulty, and then a second pass, with no sight of the prompt that produced them, is handed the claims cold and asked to break them. Anything it doubts is rejected before a human ever reviews it.

The question bank's batch-writing screen: pickers for who is playing, a category with its current question count, how many questions to write, a difficulty, an optional instruction box and a model, above an estimated cost of about eleven cents and a button reading Write 10 questions. — Two details worth pointing at. The audience bands are described by **formative years rather than age** — 55 to 75 reads as “roughly 1961 to 1996” — because that is what actually decides whether somebody knows the answer. And the estimated cost of the batch is on the button before you press it, in cents, so writing questions never turns into a bill you find out about later.

Difficulty across a night is deliberately not flat. It ramps, because rounds that are uniformly easy are what make the strong players stop coming back, and a weekly trivia night lives or dies on whether the regulars return.

How it is built

Server · Node and TypeScript, websockets throughout. Game state lives in one engine with pure scoring functions, so a night can be replayed and tested without a browser.
Client · Preact. The player bundle is about 21 KB gzipped, because some of these phones are old and the venue wifi is doing its best.
Footprint · Measured, not guessed: 119 MB of RAM idle, 121 MB with a hundred players mid-question. A hundred players cost under 3 MB. A sixty-question night moves about 13 MB in total.
Hosting · A Jetson Orin Nano in a cupboard at my house, reached through a Cloudflare Tunnel. No cloud bill, no inbound ports, no certificate to renew.
Tests · 168 of them, run against a real build rather than mocks, because the bug that ends a trivia night is never the one a mock would catch.

Why self-hosted, specifically. The rec center's guest wifi has client isolation turned on, which silently stops devices on the same network from reaching each other and produces no error that explains why. A server in that room is unreachable from the phones no matter how well it is configured. Put the server on the internet instead and the phones go out and come back in, which isolation does not stop. The tunnel was the cheapest way to do that from hardware I own.

Seeing it

The game is at trivia.gmdeckard.com and it is genuinely running right now. Fair warning before you click: joining needs the room code shown on the big screen in the room, and the host and MC screens are behind a password, so from outside you will reach a join form you cannot complete. That is the point of the room code. The screens above are the honest version of what a night looks like.

The source is on GitHub.