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This page covers both email contact sync (building your mailing list) and auth emails (magic links, password resets). One provider handles both jobs.

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What Email Does in This Repo

The email service handles two things through a single provider:
  1. Contact sync — when a user signs in, they’re created as a contact in your email tool
  2. Auth emails — magic link and password reset emails are delivered through the same provider
This means you can build a mailing list, sync user data, and handle auth emails all from one place.
If contact sync fails, sign-in still works normally. Auth email delivery is stricter because the user needs that email to finish the flow.

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Pick Your Provider

Best for: Simple defaults, easy contact syncing, and templated auth emails.Loops uses transactional template IDs for auth emails, so you’ll create the email templates in Loops and reference them by ID.
NEXT_PUBLIC_EMAIL_PROVIDER=loops
LOOPS_API_KEY=your-api-key
AUTH_EMAIL_FROM="YourApp <[email protected]>"
LOOPS_AUTH_MAGIC_LINK_TRANSACTIONAL_ID=your-template-id
LOOPS_AUTH_RESET_PASSWORD_TRANSACTIONAL_ID=your-template-id
Don’t forget the transactional template IDs. Without them, Loops won’t know which email to send for magic links and password resets.

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Provider Selection

Set the provider with: 
NEXT_PUBLIC_EMAIL_PROVIDER=loops
You can optionally add a server-only override that takes priority: 
EMAIL_PROVIDER=loops
Supported values: loops, resend, brevo, none

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Setup

1

Pick a provider

Choose Loops, Resend, or Brevo based on your needs.
2

Create an account and get your API key

Sign up with your chosen provider and generate an API key.
3

Add env vars to .env.local

Add the provider-specific env vars from the tabs above.
4

Set up templates (Loops only)

If you’re using Loops, create transactional email templates for magic links and password resets, then add their IDs to your env vars.
5

Restart and test

Restart the app, sign in with a test account, and request a magic link or password reset email. Confirm the contact appears in your provider’s dashboard.

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Key Files

  • lib/email/contacts.ts — contact sync logic
  • lib/email/providers/* — provider-specific implementations
  • lib/email/auth-emails.ts — auth email delivery

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Verify It Works

Your email setup is correct if:
  • A test user signs in successfully
  • Auth emails arrive for magic link and forgot password
  • The user appears in your chosen email provider
  • The app still works even if contact sync temporarily fails

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Common Mistakes

Make sure NEXT_PUBLIC_EMAIL_PROVIDER is exactly loops, resend, or brevo. Typos will silently disable email.
Auth emails need a sender address. Without AUTH_EMAIL_FROM, delivery will fail.
Loops requires LOOPS_AUTH_MAGIC_LINK_TRANSACTIONAL_ID and LOOPS_AUTH_RESET_PASSWORD_TRANSACTIONAL_ID. Without them, auth emails won’t send.
If you reference a segment, list, or attribute that doesn’t exist in your provider, contact sync will fail silently.
EMAIL_PROVIDER=none disables everything. No contact sync, no auth emails.