Transactional Email APIs · reliability comparison
MailerSend vs Mailchimp Transactional (Mandrill): which is more reliable? (2026)
MailerSend is more reliable than Mailchimp Transactional (Mandrill), scoring 100.0 vs 90.6 out of 100. Over the last 90 days MailerSend reported 0 incidents and Mailchimp Transactional (Mandrill) reported 3, with effective uptime of 100% and 99.93% respectively.
Data updated Nov 2, 2026 · How we score
| Metric | MailerSend | Mailchimp Transactional (Mandrill) |
|---|---|---|
| Reliability score | 100.0 | 90.6 |
| Rank (transactional email APIs) | — | #5 |
| Uptime (90 days) | 100% | 99.93% |
| Incidents (90 days) | 0 | 3 |
| Partial / major outages | 0 | 0 |
| Avg time to resolve | — | 3h 4m |
| Outages we detected | 0 | 0 |
| Transparency score | 100/100 | 100/100 |
Where MailerSend and Mailchimp Transactional (Mandrill) differ
- MailerSend reported no incidents in the last 90 days, while Mailchimp Transactional (Mandrill) reported 3.
90-day uptime
MailerSend
Mailchimp Transactional (Mandrill)
- No incidents
- Degraded
- Partial outage
- Major outage
- No data
Recent MailerSend incidents
- MaintenanceSep 23, 2026 · ongoing
Affected: Email analytics, Deliverability rate, MailerSend APP, Bulk endpoint, SMTP, Email activity +2 more
- MaintenanceSep 15, 2026 · ongoing
Scheduled maintenance - Email sending affected, 5 min
Affected: Inbound routing, Bulk endpoint, SMTP, Delivery time, Email sending API
Recent Mailchimp Transactional (Mandrill) incidents
- Degraded performanceSep 17, 2026 · resolved in 38m
Delayed Deliveries via Mandrill
Affected: Delayed Deliveries via Mandrill
- Degraded performanceSep 15, 2026 · resolved in 4h 26m
Delayed Deliveries via Mandrill
Affected: Delayed Deliveries via Mandrill
- Degraded performanceSep 1, 2026 · resolved in 4h 8m
Affected: Mandrill/Transactional Delays
Full Mailchimp Transactional (Mandrill) reliability report →
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 →