What's the cheapest email API for a small SaaS?

For a small SaaS, the cheapest email API is often the one that gives you the best mix of:

• low base cost
• generous free tier
• low price per additional email
• decent deliverability
• simple API/docs

Good low-cost options

1. Amazon SES

   • Usually the cheapest at scale
   • Roughly $0.10 per 1,000 emails sent
   • Best if you’re okay with a more technical setup
   • Great for transactional emails

2. Mailgun

   • Easy API, solid developer experience
   • Has free tier, then pricing is usually higher than SES
   • Good if you want convenience over absolute lowest cost

3. Postmark

   • Excellent deliverability and developer experience
   • Usually not the cheapest, but very reliable for transactional email
   • Better if emails are critical and volume is modest

4. Resend

   • Modern API, nice DX for startups
   • Often competitive for small apps
   • Good fit if you want something simple and SaaS-friendly

5. Brevo (Sendinblue)

   • Can be cost-effective, especially at lower volumes
   • Also offers marketing features
   • API is fine, though not as developer-focused as SES/Postmark

Quick recommendation

• Cheapest overall: Amazon SES
• Best balance of cheap + easy: Resend or Mailgun
• Best deliverability for transactional: Postmark

Important note

If your SaaS sends:

• password resets / receipts / notifications → transactional provider like SES/Postmark/Resend
• newsletters / campaigns → marketing provider like Brevo/Mailchimp

If you want, I can also give you a ranked list with current pricing for your expected monthly volume (e.g. 1k, 10k, 100k emails/month).