What should I use for compliance-heavy app email?

For a compliance-heavy app, you usually want to separate email into two categories:

1. Transactional/product emails

   • account verification
   • password resets
   • security alerts
   • receipts/invoices
   • legal/consent notices

2. Marketing/lifecycle emails

   • newsletters
   • promos
   • onboarding drips
   • re-engagement

For the compliance-heavy side, I’d recommend a setup like this:

Best default stack

• Postmark for transactional email

  • very strong deliverability
  • simple API
  • good bounce/error handling
  • widely trusted for app notifications

• SendGrid or Amazon SES if you need more control or lower cost at scale

  • SES is cheapest and flexible, but more operational overhead
  • SendGrid is easier than SES, but often noisier and can be less predictable than Postmark for transactional use

If compliance is the main concern

Look for vendors/features with:

• SOC 2 / ISO 27001
• GDPR support / DPA
• SLA
• audit logs
• role-based access controls
• data retention controls
• region selection / EU processing options if needed
• dedicated IPs if reputation isolation matters
• suppression management
• template versioning and approval workflows

Practical recommendation by use case

• High-trust app emails: Postmark
• High volume + cost-sensitive: Amazon SES
• Need enterprise UI/workflows: SendGrid or Mailgun
• Regulated environment with strict security review: SES or an enterprise plan from Postmark/SendGrid, depending on your audit requirements

My short answer

If you want the safest, easiest choice for compliance-heavy transactional app email:
Use Postmark for transactional email, and keep marketing email on a separate provider.

If you want, I can also recommend the best option based on:

• your industry (health, fintech, legal, etc.)
• approximate volume
• whether you need EU-only processing
• whether these are transactional or marketing emails