Transactional Email APIs · reliability comparison
MailerSend vs Postmark: which is more reliable? (2026)
MailerSend is more reliable than Postmark, scoring 100.0 vs 68.3 out of 100. Over the last 90 days MailerSend reported 0 incidents and Postmark reported 8, with effective uptime of 100% and 99.58% respectively.
Data updated Nov 1, 2026 · How we score
| Metric | MailerSend | Postmark |
|---|---|---|
| Reliability score | 100.0 | 68.3 |
| Rank (transactional email APIs) | — | #10 |
| Uptime (90 days) | 100% | 99.58% |
| Incidents (90 days) | 0 | 8 |
| Partial / major outages | 0 | 0 |
| Avg time to resolve | — | 7h 41m |
| Outages we detected | 0 | 0 |
| Transparency score | 100/100 | 100/100 |
Where MailerSend and Postmark differ
- MailerSend reported no incidents in the last 90 days, while Postmark reported 8.
90-day uptime
MailerSend
Postmark
- No incidents
- Degraded
- Partial outage
- Major outage
- No data
Recent MailerSend incidents
- MaintenanceSep 23, 2026 · ongoing
Affected: Bulk endpoint, SMTP, Email activity, Delivery time, Email sending API, Email analytics +2 more
- MaintenanceSep 15, 2026 · ongoing
Scheduled maintenance - Email sending affected, 5 min
Affected: SMTP, Delivery time, Email sending API, Inbound routing, Bulk endpoint
Recent Postmark incidents
- Degraded performanceOct 27, 2026 · resolved in 1h 43m
- MaintenanceOct 7, 2026 · resolved in 3h
- Degraded performanceSep 28, 2026 · resolved in 2h 6m
- Degraded performanceSep 28, 2026 · resolved in 3h 59m
- Degraded performanceSep 22, 2026 · resolved in 20m
- Degraded performanceSep 17, 2026 · resolved in 1h 33m
Other transactional email APIs to consider
- Mailjet · #1 · 100% uptime
- Mailtrap Email Sending · #2 · 99.99% uptime
- Loops · #3 · 99.98% uptime
- Twilio SendGrid · #4 · 99.98% uptime
See the full most reliable transactional email apis ranking →