Auth providers
The emails your auth provider sends, tested end to end.
Supabase, Clerk, Auth0, Firebase, Auth.js and Better Auth all email your users: a code or link to verify, sign in or reset a password. Each has its own sending rules, and the default ones are often limited to a few emails or a few addresses. These guides cover what each provider sends, what stops it arriving, and how to test every email by hand or from your tests.
Supabase Auth
Confirmation, magic-link, code and reset emails, and why the default sender won't email your test addresses.
Read the guide →Clerk
Verification codes, email links and resets, when test-mode addresses aren't enough, and the development email cap.
Read the guide →Auth0
Verification links, passwordless codes and resets, and the built-in email provider's limits.
Read the guide →Firebase Authentication
Verification, reset and email-link sign-in emails on the web, and the daily sending limits.
Read the guide →Auth.js (NextAuth)
Magic-link sign-in through your own email provider, its expiry, and what stops the email arriving.
Read the guide →Better Auth
Verification, reset, magic-link and email OTP emails through your own provider, and their short expiry.
Read the guide →
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