Prompt
What should I use for API-based app email sending?
Latest observation
Oct 5, 2026
OpenAI APIWeb search: off
For API-based app email sending, the best choice is usually a transactional email service rather than a regular mailbox provider.
Good options
- SendGrid — popular, easy to integrate, good deliverability tools
- Mailgun — strong API, good for developers
- Postmark — excellent for transactional emails, very reliable deliverability
- Amazon SES — cheapest at scale, but a bit more setup
- Resend — modern API, nice developer experience, especially for app emails
What to choose
- Best overall simplicity: Resend or Postmark
- Best at scale / lowest cost: Amazon SES
- Most common general-purpose option: SendGrid
- Developer-friendly alternative: Mailgun
Recommendation
If you’re sending:
- password resets, signups, receipts, alerts → use Postmark or Resend
- high volume / cost-sensitive → use Amazon SES
- marketing + transactional in one place → consider SendGrid
Quick rule
Avoid using Gmail/Outlook SMTP for an app backend. They’re fine for personal use, but not ideal for production apps.
If you want, I can also recommend the best option based on your stack, budget, and expected email volume.