Play Cosmillion with friends, without spoiling anything

How challenge links work

Finish a daily launch and the result screen offers a challenge link. That link is a URL with a compact code in it — the launch number and your final score. When a friend opens it, the game reads those two values, shows the same seven prompts from that launch, and after their final answer puts a single line on the result screen: either they beat your score, or your score beat them.

1. 01

   Play today's launch

   Seven prompts, 25 seconds each. Finish the launch so the result screen appears. Your score is the number the challenge will compare against.

2. 02

   Copy the challenge link

   Tap “copy challenge link” on the result screen. The URL contains the launch number and your score — nothing else. No answers, no prompts, no tiers.

3. 03

   Send it

   Paste it into a group chat, a direct message or an email. There is no invite code, no friend request and no notification system. It is a link, and links work everywhere.

4. 04

   They play the same seven

   The game opens on that launch's prompts with a banner showing the score to beat. They play once, at their own pace, with no time pressure beyond the normal timer.

5. 05

   Compare, gloat or commiserate

   Their result screen shows the head-to-head. That is the whole challenge: no leaderboard, no ranking, no season points. Just a clean answer to “who thinks stranger?”.

Why the link cannot spoil the game

Spoilers are the failure mode of daily games. If a shared result leaks the answer, the ritual is ruined for everyone who has not played yet. Cosmillion's challenge link is deliberately minimal: launch number plus score. It tells your friend what bar to beat and nothing about how you got there.

The result screen's share text is spoiler-free by the same design. It reports your score, a rarity summary and the launch number — the sort of thing you can post publicly without wrecking the day for someone who has not played yet. If you want to talk about a specific answer, wait until everyone in the conversation has finished. That etiquette is the only rule the game cannot enforce.

No sign-up, for either player

Cosmillion has no accounts, which sounds like a technical detail until you try to get a friend to play something. “Create an account” is where most invitations die. There is no account creation here at all: open the link, read the prompt, type an answer. The game stores your progress in your own browser, so there is nothing to log into and nothing to recover.

That also makes the challenge genuinely equal. Your friend is not a “guest” with a limited experience, and you are not a premium player with extra modes. Everyone gets the same seven prompts, the same 25 seconds and the same free archive. The only difference between players is the answers they choose.

If you are the one being challenged and you have not played today's launch yet, you have a choice: play the challenge and then play your own daily launch, or the other way around. Either order is fine. The challenge run is fun-only and will not affect your streak, best or history.

The group chat formats that actually work

Cosmillion challenges are asynchronous by design, which is why they fit real group chats better than most multiplayer games. Nobody has to be online at the same time, and nobody has to install anything.

• The daily score drop. Everyone plays the same launch and posts their score and best answer. One message per person, no thread, no spoilers.
• The chain challenge. Send your link to one person; whoever finishes can send their own link onward. The score bounces around the chat for the rest of the day.
• The family table. At dinner, everyone opens the same launch on their own phone. The first person to finish reads out the prompt, and the table hears the reveals together. Low scores become the evening's entertainment.
• The long-distance ritual. A five-minute call once a day: both people play their own launch, then compare scores and the rarest answer they found. It is a tiny shared appointment that does not need a calendar.
• The office lunch league. A Friday challenge link to the team chat. No spreadsheet, no sign-up, no season fees; the score is the whole ranking.

A small piece of etiquette makes all of these better: post your score, not the prompt. The daily page explains why the seven prompts are shared and why the challenge result compares cleanly across players.

Why the comparison is fair

For a challenge to mean anything, both players need the same test. Cosmillion's launch is fixed: launch 42 is the same seven prompts for everyone who opens it, and each prompt's answer board is the same curated board with the same six tiers. There is no dynamic difficulty, no personalised prompt set and no way to buy a better board.

The timer is the only variable that is not shared, because it runs on each player's device. Somebody on a fast phone and somebody on an old laptop both get 25 seconds, but the input experience differs by a second or two. That is the small, honest cost of a game that runs entirely in the browser without a server clock — and it is the same cost for both sides of a challenge.

One thing challenges deliberately do not do is affect the daily board. A challenge run is not a second daily attempt, so nobody can improve their streak or best score by replaying through a link. The daily score stays one attempt; the challenge stays a side quest.

Play with friends: questions, answered