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Overview

Featul uses Resend as the email service provider for:
  • Email verification (OTP codes)
  • Welcome emails
  • Password reset emails
  • Workspace invitations
  • Reservation confirmations
  • Report notifications

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Resend Setup

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1. Create Resend Account

  1. Sign up at Resend
  2. Verify your email address
  3. Add and verify your sending domain

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2. Domain Verification

  1. Go to Resend Dashboard > Domains
  2. Add your domain (e.g., featul.com)
  3. Add the provided DNS records:
    • SPF record (TXT)
    • DKIM record (TXT)
    • DMARC record (TXT)
  4. Wait for verification (usually a few minutes)
For development, you can use Resend’s test mode which allows sending to verified email addresses without domain verification.

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3. Generate API Key

  1. Go to Resend Dashboard > API Keys
  2. Create a new API key with sending permissions
  3. Copy the API key (you won’t be able to see it again)

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4. Environment Variables

Add these to your .env file:
.env
RESEND_API_KEY=re_your_api_key_here
RESEND_FROM=featul <no-reply@featul.com>
  • RESEND_API_KEY: Your Resend API key
  • RESEND_FROM: The “From” address and name for outgoing emails
Configuration in code: packages/auth/src/email/transport.ts:9-10
Make sure the domain in RESEND_FROM matches your verified domain in Resend.

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Email Types

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Welcome Email

Sent automatically when a new user signs up: 
await sendWelcome(to, name)
Code reference: packages/auth/src/email.ts:10-13 Triggered by: packages/auth/src/auth.ts:252-261

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Email Verification (OTP)

Sent for:
  • Email verification during sign-up
  • Sign-in verification (if enabled)
  • Password reset
await sendVerificationOtpEmail(email, otp, type)
Code reference: packages/auth/src/email.ts:15-19 Triggered by: packages/auth/src/auth.ts:232-237
OTP codes are 6-digit numeric codes that expire after a short time (configured in better-auth).

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Workspace Invitation

Sent when a user is invited to join a workspace: 
await sendWorkspaceInvite(to, workspaceName, inviteUrl)
Code reference: packages/auth/src/email.ts:21-25

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Reservation Email

Sent to confirm workspace subdomain reservations: 
await sendReservationEmail(to, slug, confirmUrl)
Code reference: packages/auth/src/email.ts:27-31

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Report Email

Sent when content is reported: 
await sendReportEmail(to, props)
Code reference: packages/auth/src/email.ts:32-36

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Email Transport

The email transport implementation uses the Resend API: 
const res = await fetch("https://api.resend.com/emails", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${apiKey}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({ from, to, subject, html, text }),
})
Code reference: packages/auth/src/email/transport.ts:8-34

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Development Mode

If RESEND_API_KEY is not set, emails will be logged to the console instead: 
[email:dev] to=user@example.com subject=Welcome to featul
This allows development without configuring a real email service. Code reference: packages/auth/src/email/transport.ts:12-15
In test mode (non-production with invalid credentials), failed emails will log warnings instead of throwing errors.

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Email Templates

Email templates are React components rendered to HTML:
  • welcomeemail.tsx: Welcome email template
  • verifyemail.tsx: OTP verification email template
  • inviteemail.tsx: Workspace invitation template
  • reserveemail.tsx: Reservation confirmation template
  • reportemail.tsx: Report notification template
Templates support custom branding (logo, colors) for white-label deployments. Template location: packages/auth/src/email/

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Email Rendering

Emails are rendered with both HTML and plain text versions: 
const { html, text } = await renderWelcomeEmail(name, brand)
await sendEmail({ to, subject, html, text })
This ensures compatibility with all email clients.

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Rate Limiting

Email sending is indirectly rate-limited through authentication endpoint rate limits:
  • Email verification: 5 requests per 60 seconds
  • Password reset: 3 requests per 5 minutes
Code reference: packages/auth/src/auth.ts:219-221 See the Authentication Configuration page for rate limit setup.

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Alternative Email Providers

To use a different email provider (SendGrid, Mailgun, etc.):
  1. Modify packages/auth/src/email/transport.ts
  2. Replace the Resend API call with your provider’s API
  3. Update environment variables accordingly
Example for SendGrid: 
const apiKey = process.env.SENDGRID_API_KEY

const res = await fetch("https://api.sendgrid.com/v3/mail/send", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${apiKey}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    personalizations: [{ to: [{ email: to }] }],
    from: { email: from },
    subject,
    content: [
      { type: "text/html", value: html },
      { type: "text/plain", value: text },
    ],
  }),
})

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