I’m building a SaaS app and need reliable email sending, what should I use?

For a SaaS app, the safest default is to use a dedicated transactional email provider rather than sending directly through your own SMTP server.

Best options

1. Postmark

• Great deliverability for transactional emails
• Simple API
• Excellent for things like:
  • sign-up confirmations
  • password resets
  • receipts
  • notifications

Best if: you care most about emails landing in inboxes reliably.

2. SendGrid

• Very common and flexible
• Good if you also need marketing email features later
• Large ecosystem and integrations

Best if: you want a broad platform with transactional + marketing options.

3. AWS SES

• Very low cost
• Reliable, but more technical to set up
• Best if you already use AWS and want to keep costs down

Best if: you’re cost-sensitive and comfortable with more configuration.

4. Mailgun

• Strong API and developer-friendly
• Good for transactional email
• Solid for scaling

Best if: you want a developer-focused tool with good control.

My recommendation

If you’re just starting and want the least pain:

• Use Postmark for transactional email.

If you need both transactional and marketing emails in one place:

• Use SendGrid.

If you’re on AWS and want lower cost:

• Use AWS SES.

Important setup tips

No matter which provider you choose, make sure to:

• Verify your domain with SPF, DKIM, and DMARC
• Use a separate sending domain or subdomain like mail.yourdomain.com
• Set up bounce and complaint handling
• Warm up the domain/IP if you’ll send in volume
• Keep transactional and marketing emails separate

Avoid

• Sending directly from Gmail/Outlook SMTP for production SaaS
• Using your app server’s built-in mail function without a proper email service
• Mixing marketing blasts with product-critical emails on the same stream

If you want, I can also give you a provider recommendation based on your stack, budget, and email volume.