MXToolbox is a popular email diagnostic tool, but it has limitations for developers and teams who need API access, automation, and integration capabilities.
| Feature | mailcheck | MXToolbox |
|---|---|---|
| Free API Access | ✓ 50 req/hr | ✗ Paid only |
| REST API | ✓ JSON responses | ✗ GUI only (free) |
| Batch Checking | ✓ Multiple domains | ⚠ Limited |
| MTA-STS Check | ✓ | ✗ |
| BIMI Check | ✓ | ✗ |
| Open Source | ✓ Self-hostable | ✗ |
| Crypto Payments | ✓ BTC/LTC/XMR | ✗ |
| 0–100 Score | ✓ Quantified | ⚠ Pass/Fail only |
No signup needed. Just curl:
curl https://korpo.pro/api/v1/check/yourdomain.com
See scores for popular domains: Gmail · Microsoft · ProtonMail