Magic-link sign-in
Offer passwordless authentication without requiring users to create or remember passwords.
Auth.js · Const
Postmark
Postmark is an Auth.js email provider for passwordless sign-in. It sends tokenized magic links and requires a database adapter to store verification tokens.
How it works
Postmark is an email provider for passwordless authentication. Auth.js sends a verification link containing a token, stores the token through a database adapter, and signs the user in after the link is used.
Syntax
import Postmark from "next-auth/providers/postmark"
providers: [Postmark]Key points
- Postmark enables passwordless sign-in through email links that carry verification tokens.
- A verification token normally expires after 24 hours.
- Using a valid link can create the account and complete sign-in.
- Postmark may be combined with OAuth providers or used as the sole sign-in method.
- The conventional AUTH_POSTMARK_KEY variable is automatically recognized.
- With configuration complete, sign-in starts through the Auth.js sign-in endpoint.
Common mistakes
- Email sign-in requires a configured database adapter because verification tokens must be stored.
- The sending domain must be added to Postmark and match the domain used by the provider's from address.
- Set up the database adapter before enabling the provider.
Example: Postmark email sign-in setup
import NextAuth from "next-auth"
import Postmark from "next-auth/providers/postmark"
import { PrismaAdapter } from "@auth/prisma-adapter"
import { prisma } from "./prisma"
export const { handlers, auth, signIn, signOut } = NextAuth({
adapter: PrismaAdapter(prisma),
providers: [Postmark],
})Configure the provider with a database adapter; AUTH_POSTMARK_KEY is discovered automatically.
When to use it
Combined authentication methods
Provide email authentication alongside social login options.
Email authentication with session management
Use Auth.js sessions while retaining persistent verification-token storage.
Interview questions
QHow does Postmark authentication work?
Postmark provides passwordless email authentication. Auth.js sends a verification token in a link, and following a valid link creates or signs into the corresponding account.
Follow-up: Why is an adapter required? Verification tokens need persistent storage, so email sign-in cannot operate without a database.
QWhat session strategies are supported?
The provider can use either JWT-managed or database-managed sessions, but a database is still required for the email verification token. Configure an adapter in the Auth.js options.
Follow-up: What must be changed when using a custom environment-variable name? Pass that variable explicitly as the provider's apiKey option.
QHow is the Postmark API key configured?
Set AUTH_POSTMARK_KEY to the Postmark API key and use Postmark in the providers array. Auth.js detects that conventional variable automatically; an alternative variable name must be passed manually.
Follow-up: What external Postmark setup is needed? Add the sending domain to Postmark and generate an API key in its dashboard.
Related
Email ProvidersVerification Tokendatabase adapterOAuth providersAUTH_POSTMARK_KEYsignIn