GDPR-Compliant Email API: What You Actually Need

GDPR compliance for transactional email is often overcomplicated. Here's what actually matters and how to implement it properly.

What GDPR Requires for Email

For transactional email, GDPR applies to the personal data you process—primarily email addresses and any personalization data in the email content.

The Core Requirements

1. Lawful basis — Transactional emails typically fall under "legitimate interest" or "contractual necessity"
2. Data minimization — Only process what you need
3. Storage limitation — Don't keep data forever
4. Security — Encrypt in transit and at rest
5. Transfer safeguards — If data leaves the EU, you need legal mechanisms

The Data Transfer Problem

Most email APIs are US-based. When you send an email through Resend, SendGrid, or Postmark, your customer's email address travels to US servers.

This requires:

• Standard Contractual Clauses (SCCs) — Legal agreements for the transfer
• Transfer Impact Assessment — Your evaluation of the risk
• Supplementary measures — Additional safeguards you implement

This isn't illegal, but it creates ongoing compliance overhead.

The Simpler Approach: EU Data Residency

If your data never leaves the EU, you eliminate the transfer problem entirely:

• No SCCs needed for the email provider
• No Transfer Impact Assessment
• Simpler DPA (Data Processing Agreement)
• Easier audit trail

Implementing GDPR-Compliant Email with Truncus

1. Data Processing Agreement

Truncus provides a standard DPA that covers:

• Data processing scope (email addresses, message content)
• Security measures (TLS, encryption at rest)
• Subprocessor list (AWS EU, no US transfers)
• Data deletion procedures

2. Technical Implementation

import { Truncus } from '@truncus/node';

const truncus = new Truncus({
  apiKey: process.env.TRUNCUS_API_KEY,
  // Data stays in EU
  region: 'eu-west-1',
});

// Send with only necessary data
await truncus.emails.send({
  from: 'noreply@yourapp.com',
  to: userEmail,
  subject: 'Your order confirmation',
  html: orderConfirmationHtml,
  // Set retention for GDPR compliance
  metadata: {
    retention_days: 30,
  },
});

3. Webhook Data Handling

When you receive webhooks, process them appropriately:

// Webhook handler
app.post('/webhooks/email', async (req, res) => {
  const event = req.body;

  // Log delivery status (legitimate interest)
  await logDeliveryEvent({
    messageId: event.message_id,
    status: event.type, // delivered, bounced, etc.
    timestamp: event.timestamp,
  });

  // Don't store the full payload long-term
  // Only keep what you need for operations

  res.status(200).send('OK');
});

4. Data Retention

Truncus automatically deletes:

• Email content: 30 days after send
• Delivery logs: 90 days
• Analytics data: Aggregated, no personal data retained

You can request earlier deletion via API.

Checklist: GDPR-Compliant Email Setup

Requirement	How Truncus Helps
Data Processing Agreement	Standard DPA provided
EU data residency	All data stays in EU
Encryption in transit	TLS 1.3 required
Encryption at rest	AES-256 encryption
Access controls	API key scoping, audit logs
Data deletion	Automatic retention limits + API
Subprocessor transparency	Published subprocessor list

What You Still Need to Do

Using a GDPR-compliant email API doesn't make you compliant automatically. You still need:

1. Privacy policy — Disclose you use transactional email services
2. Lawful basis — Document why you send each type of email
3. Data minimization — Don't put unnecessary personal data in emails
4. Subject access requests — Process SARs within 30 days

Getting Started

1. Create your account
2. Download the DPA from your dashboard
3. Configure your domain
4. Send your first email

Questions about GDPR compliance? Contact us at privacy@truncus.co