A chat of six people can feel empty or it can feel like a crowd. The difference is usually whether those six people get to change what happens on screen. This guide is about games to play on stream with viewers: the different ways chat can take part, what each platform gives you for it, and one format we built into our own game for exactly this.
A note before we start: we make Cosmic Starship, and it appears in the second half of this page. The first half applies to whatever you play.
Four ways viewers can play along
1. Viewers join the game itself
Party games designed for streaming let viewers play or vote from their own phone. Jackbox Games, for instance, says on its about page that its games take up to 10,000 audience members alongside the players, joining through jackbox.tv with the room code. Because they join through a website, this works the same whether you stream on Twitch, YouTube, TikTok or Kick. Not every game in every pack supports the audience, so check before you plan a night around it.
2. Chat commands become players
Some games read your chat and turn each viewer who types a command into a racer or a fighter. Marbles on Stream on Steam is the best-known: viewers type a command in chat and get a marble in a physics race. These games connect to a specific platform’s chat, so check which platforms a game supports before you build a segment around it.
3. Chat makes the decisions
You play; chat decides. Which route, which loadout, which difficulty, whether to take the risky fight. This works in any game and on any platform, with the built-in poll tools or a simple “type 1 or 2”. It is the easiest place to start, and it is how our own game works with chat.
4. One viewer plays with you
Co-op with a regular, or with whoever wins a giveaway, turns a viewer into a guest star. Games that run in a browser make this easier, because your guest has nothing to install.
What each platform gives you
- YouTube: channel owners can run polls in live chat with two to four options, according to YouTube’s live chat help page.
- Twitch: polls and Channel Points Predictions are available to Affiliates and Partners, as Twitch’s developer documentation and its Predictions announcement say. Before you reach Affiliate, a chat bot or plain “type 1 or 2” votes do the job.
- TikTok LIVE and Kick: their interactive tools change often and differ by region and account, so check the platform’s own help pages. Chat votes by typing work everywhere.
Whatever the tool, the rule is the same: keep votes short (30 to 60 seconds), say the options out loud for people watching without chat open, and act on the result immediately.
A format to try: chat builds the fleets
We built Who Would Win?, the battle simulator in Cosmic Starship, partly with streams in mind. You pick two fleets from fourteen civilizations, up to 30 capital ships and 150 fighters a side, and watch them fight to the last ship in 3D. Both sides fly the same AI by the same rules, so there is no hidden difficulty setting favouring one side.
Here is how we would run it as a segment:
- Turn on the equal budget. Both sides buy their fleets with the same money, from a ₵10,000 skirmish to ₵160,000.
- Chat picks one fleet, you pick the other. Or split chat into two teams. Take suggestions for a minute, then build both sides on screen so everyone sees the choices.
- Vote on the winner before the fight. Use Predictions, a poll or chat votes, depending on your platform.
- Run the battle at 1× for the opening, then speed it up. The simulator goes from ½× to 4× speed, and the camera follows the action and slows down when a capital ship dies.
- Post the matchup link in chat. Every matchup is a link, so viewers can rerun it, swap the sides or try a new seed after the stream.
Why equal budgets make better segments: the prices in the simulator are not guesses. We set them by measuring. After calibrating on 1,176 one-on-one duels and fighter-swarm stands and fitting the prices to 1,800 random mixed-fleet battles, we ran 480 new battles: the fleet with the higher value won 93.5% of them. With equal budgets, fights come out close. In our testing the winning fleet kept 44% of its strength on average, against 65% when two random fleets with no budget met. In other words, chat cannot predict the result just by looking at the numbers, which is what makes a prediction worth making.
One more detail that matters on stream: a battle’s seed replays it exactly. If chat says the result was a fluke, run the same matchup with a new seed and settle it.
The simulator also records its own clip with sound, in 16:9 or 9:16, with the matchup, strength bars, timer and result drawn on the picture. That gives you a short video of each fight to post the same day.
Playing with one viewer in co-op
Cosmic Starship has online co-op for two: each player flies their own capital ship on their own device in the same battle. One of you opens a room (public, or private with a six-letter code and an invite link) and the other joins it from the Co-op tab. The battle runs directly between the two browsers.
Two practical notes. First, both players must run the same version of the game: a room opened on an older version cannot be joined from a newer one. Second, some strict networks (offices, schools, some mobile data) block direct connections between browsers, so do a test with your guest before going live rather than discovering it on air.
Keeping it fair and fun
- Repeat the rules every time someone new arrives. One sentence is enough: “Chat picks the left fleet, I pick the right, predict the winner.”
- Do not let the loudest chatter win every vote. Rotate who picks, or use the platform’s poll so every voice counts once.
- Keep a running score on screen. Chat versus streamer over a whole evening gives viewers a reason to come back next week.
- Know when to switch. Interactive segments burn out. Twenty to forty minutes, then back to the main game, works better than a whole night of one gimmick.
Want to see what your chat would build? Open Who Would Win? in your browser, or read about choosing a game to stream if you are just starting out.