Transactional Email APIs · reliability comparison
Mailgun vs Mailchimp Transactional (Mandrill): which is more reliable? (2026)
Mailchimp Transactional (Mandrill) is more reliable than Mailgun, scoring 90.6 vs 83.2 out of 100. Over the last 90 days Mailgun reported 10 incidents and Mailchimp Transactional (Mandrill) reported 3, with effective uptime of 99.84% and 99.93% respectively. Mailgun resolves incidents faster on average (1h 43m).
Data updated Nov 1, 2026 · How we score
| Metric | Mailgun | Mailchimp Transactional (Mandrill) |
|---|---|---|
| Reliability score | 83.2 | 90.6 |
| Rank (transactional email APIs) | #7 | #5 |
| Uptime (90 days) | 99.84% | 99.93% |
| Incidents (90 days) | 10 | 3 |
| Partial / major outages | 3 | 0 |
| Avg time to resolve | 1h 43m | 3h 4m |
| Outages we detected | 0 | 0 |
| Transparency score | 100/100 | 100/100 |
Where Mailgun and Mailchimp Transactional (Mandrill) differ
- Mailgun reported 3.3× as many incidents as Mailchimp Transactional (Mandrill) over the last 90 days (10 vs 3).
- Mailgun had 3 partial or major outages, compared with 0 for Mailchimp Transactional (Mandrill).
- Mailgun fixes problems faster: 1h 43m on average, against 3h 4m for Mailchimp Transactional (Mandrill).
- Mailgun's longest outage on record lasted 3h 37m (May 25, 2026); Mailchimp Transactional (Mandrill)'s lasted 4h 26m (Sep 15, 2026).
90-day uptime
Mailgun
Mailchimp Transactional (Mandrill)
- No incidents
- Degraded
- Partial outage
- Major outage
- No data
Recent Mailgun incidents
- Degraded performanceOct 28, 2026 · resolved in 1h 4m
Affected: Inbound email processing
- Degraded performanceSep 30, 2026 · resolved in 42m
Affected: Inbound email processing
- Degraded performanceSep 14, 2026 · resolved in 58m
Affected: Inbound email processing
- Major outageSep 4, 2026 · resolved in 17m
Affected: API, SMTP, Outbound Delivery, Inbound email processing, Events & Logs, Stats and Analytics
- InformationalSep 4, 2026 · resolved in 34m
- Degraded performanceAug 31, 2026 · resolved in 7h 14m
Affected: Events & Logs
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 →