Do I need to register or set a password?

No. There is no account and no password. Opening the page hands you a working address; your browser session (a single cookie plus local storage) is what connects you to that inbox. There is nothing to log into — which is why searches for a “temp mail login” or a “temp mail with password” usually end in confusion.

Why it's designed this way

• Speed. The whole value is an inbox in zero steps. Registration would add the exact friction the tool exists to remove.
• Privacy. No signup means no name, no recovery email, no phone number — nothing to store, breach, or sell.
• Ephemerality. Addresses live 10 minutes by default. Passwords on a 10-minute mailbox would be security theater.

The trade-off you're accepting

Without a password, the inbox is protected only by obscurity: anyone who learns the exact address could open it while it lives. Random ten-character names make guessing impractical, but a custom name like john91 is easier to stumble upon. Two rules follow: keep sensitive material out of temp inboxes, and prefer the random name unless you have a reason not to. And since there's no login, an expired address can never be recovered — anything that might need a password reset later belongs on a real inbox.

If a service demands an address that can hold a password, that's its way of saying the account is meant to last — use your real email there.