Choosing the right SMTP server is one of the most consequential technical decisions for any business that sends email at scale. The wrong choice means deliverability problems, throttling, blacklisted IPs and emails that quietly land in spam. The right choice means inbox placement, reliable APIs and a deliverability dashboard that tells you exactly what is happening.
The four main types of SMTP server
| Type | Best for | Trade-off |
|---|---|---|
| Personal SMTP (Gmail, Outlook) | Individuals, < 500 emails/day | Daily limits, no transactional, no analytics |
| Self-hosted (Postfix, Exim) | Full technical control | You own IP reputation, blacklist handling, queues |
| Hosted SMTP (cPanel, Plesk) | Small business websites | Shared IPs with unknown neighbours |
| Managed SMTP relay (Mailpro) | Transactional + marketing at any volume | Pay per email or monthly plan |
Decision criteria
Pick the SMTP type by answering five quick questions:
- Volume: < 500/day → ISP. Anything more → managed relay.
- Transactional vs marketing: transactional needs < 1s latency — relay or API.
- Compliance: GDPR, HIPAA, ISO 27001 — managed providers come pre-certified.
- Engineering capacity: a self-hosted Postfix is one full-time DevOps engineer.
- Engagement tracking: opens/clicks/bounces require relay or API.
Why most businesses end up with a managed relay
Managed providers (like Mailpro) absorb the four hardest parts of running email infrastructure: maintaining IP reputation, configuring SPF/DKIM/DMARC for every sending domain, handling bounces and complaints, and following ever-changing ISP rate limits. They typically achieve 98%+ inbox placement out of the box.
Detailed comparison: Mailpro vs alternatives
| Criterion | ISP SMTP | Self-hosted | Mailpro relay |
|---|---|---|---|
| Daily volume | ~500 | Unlimited | Per plan |
| Setup time | 5 min | Days | 5 min |
| Maintenance | None | Constant | None for you |
| Deliverability dashboard | No | Build yourself | Built-in |
| SPF/DKIM/DMARC | Manual | Manual | Guided |
| Cost at 100k emails/month | N/A | €500+ ops | From a few euros |
Choosing Mailpro’s SMTP relay
Activate it from Account → SMTP credentials, generate a username and password, paste them into your application’s SMTP settings (Magento, WooCommerce, WordPress, Salesforce, Odoo) and you are sending in minutes. See what is SMTP relay service and 10 factors to check before choosing an SMTP server.
Comparing hosted providers with self-managed AWS infrastructure? See our guide to the best Amazon SES alternatives.
Pick the right SMTP for your scale
Mailpro’s SMTP relay handles authentication, deliverability, tracking and abuse for you. Compare with the Email API in our SMTP vs API FAQ.