How do I sign in? There's no password

There is no password. Enter your email, we send you a 6-digit code, you type it in. That is also how you create an account: the first time you sign in with an address, the account is made for you.

Signing in

1. Tap Sign in, enter your email, tap Send Login Code.
2. Open your email. The message is from [email protected] and contains a 6-digit code.
3. Type the code. It works once and expires after 10 minutes.

You stay signed in on that device for as long as you keep using it. A device you don't touch for 30 days is signed out.

The code didn't arrive

• Check Spam or Junk. In Gmail, also check the Promotions and Updates tabs.
• Using a school email? Many school mail systems quarantine automated messages. Look for a "quarantine digest" email, or ask your IT desk to allow mail from [email protected]. If your instructor invited you on your school address, you need to use that same address, so it's worth fixing rather than switching.
• Check the spelling of the address you typed. A code sent to a typo never arrives.
• Wait two minutes before tapping Send a new code. Only the newest code works.
• Temporary or disposable email addresses are refused. Use a real inbox.
• "Too many attempts" means codes were requested very rapidly. Wait five minutes and try once.

"That code is incorrect or has expired"

Codes are single-use and last 10 minutes. Request a new one and use only the newest email; an older code in the same inbox won't work.

Signed in on the website but not the app?

They're the same account. Sign in to the app with the same email address and everything is there.