No. You can use Proof without an Every account.
Proof is available to everyone, and basic use does not require login.
Using Proof without an account
You can create and work in Proof documents without signing in.
This makes it easy to quickly collaborate with other people—or with your AI agent—without going through an account setup flow first.
What you get when you sign in with Every
If you sign in with an Every account, you get access to a continually updating library of the Proof documents you’ve created.
In other words:
No account required for basic use
Every account recommended if you want ongoing access to your created-document library inside Proof
Where to get started
Start here: proofeditor.ai
You can also learn more in Every’s launch post: Introducing Proof.