Quick answer: Sign up for Muse, then within 48 hours open Settings → Redeem token (mobile) or Settings → General → Usage → Redeem invite code (web), enter a 6-character invite code, and confirm. You get 1 billion Muse tokens; the code's owner gets 1 billion too.
The clock starts at sign-up. The 48 hours run from when your account is created, not from when you find a code. Redeem the same day you join.
One code per account, ever. Pick a code and use it once — codes cannot be stacked.
You need a code from someone else. Your own code is for other people; it does not work on your account.
Availability: Muse is currently open in the US and Canada, for users 18+. An invite code does not change regional availability.
Step by step
Get a code. Claim one free from the pool home page. Copy it exactly — codes are 6 characters and easy to mistype (O vs 0, I vs 1).
Create your Muse account in the app or at muse.ai, if you have not already.
Open the redeem field. Mobile app: Settings → Redeem token. Web: Settings → General → Usage → Redeem invite code.
Enter the code and confirm. The 1 billion tokens appear in your balance as a separate pool. Check Settings → Usage to see them.
If the code does not work
The three usual causes are: the code is full (each code works for about 20–30 people), your account is past the 48-hour window, or a character was mistyped. A full code is not your fault — claim a different one and redeem it right away. Every error and fix is listed in the troubleshooting guide.
After you redeem: fill your own code
Your account now has its own invite code. Every new user who redeems it earns you another 1 billion tokens, up to the cap. Submit it to the fill-up page and new users from this pool will be served your code first.