I need an email API that won't make debugging impossible when a customer says they never got the message. What should I use?

Use an email provider that gives you message-level event tracking and a searchable activity log. The key features you want are:

• Delivery events: sent, delivered, bounced, deferred, dropped, opened, clicked
• Webhook/event stream: so you can store delivery history in your app
• Message IDs: to trace one specific email end-to-end
• Suppressions management: to see if an address was blocked, bounced, or unsubscribed
• Inbound support or reply tracking if you need two-way email
• Debug-friendly logs/UI: so support can look up exactly what happened

Good options

• Postmark — best if you want very clear delivery logs and easy debugging

  • Excellent message traceability
  • Very strong for transactional email
  • Great dashboard for support cases

• SendGrid — flexible and widely used

  • Lots of features, but can be a bit noisier/more complex
  • Good event webhooks and logs if configured well

• Mailgun — strong API and logs

  • Good for developers who want deeper event data
  • Can be more technical to set up

• Amazon SES + SNS/EventBridge — cheapest at scale

  • Powerful, but debugging is more DIY
  • You’ll need to build your own visibility layer

My recommendation

If your main concern is “a customer says they never got it”, start with Postmark. It’s one of the best choices for transactional email because it makes tracing a message much easier than most alternatives.

What to look for in any provider

Ask:

1. Can I search by recipient, subject, or message ID?
2. Do I get bounce/delivery webhooks?
3. Can I see the exact SMTP response or rejection reason?
4. Can I tell whether the email was suppressed or deferred?
5. Can I retain logs long enough for support troubleshooting?

If you want, I can also give you a side-by-side comparison of Postmark vs SendGrid vs Mailgun vs SES focused specifically on debugging and support.