Transactional Email APIs · reliability comparison
Mailchimp Transactional (Mandrill) vs SparkPost (Bird): which is more reliable? (2026)
Mailchimp Transactional (Mandrill) is more reliable than SparkPost (Bird), scoring 90.6 vs 87.7 out of 100. Over the last 90 days Mailchimp Transactional (Mandrill) reported 3 incidents and SparkPost (Bird) reported 8, with effective uptime of 99.93% and 99.90% respectively. SparkPost (Bird) resolves incidents faster on average (2h).
Data updated Nov 1, 2026 · How we score
| Metric | Mailchimp Transactional (Mandrill) | SparkPost (Bird) |
|---|---|---|
| Reliability score | 90.6 | 87.7 |
| Rank (transactional email APIs) | #5 | #6 |
| Uptime (90 days) | 99.93% | 99.90% |
| Incidents (90 days) | 3 | 8 |
| Partial / major outages | 0 | 0 |
| Avg time to resolve | 3h 4m | 2h |
| Outages we detected | 0 | 0 |
| Transparency score | 100/100 | 100/100 |
Where Mailchimp Transactional (Mandrill) and SparkPost (Bird) differ
- SparkPost (Bird) reported 2.7× as many incidents as Mailchimp Transactional (Mandrill) over the last 90 days (8 vs 3).
- SparkPost (Bird) fixes problems faster: 2h on average, against 3h 4m for Mailchimp Transactional (Mandrill).
- Mailchimp Transactional (Mandrill)'s longest incident on record lasted 4h 26m (Sep 15, 2026); SparkPost (Bird)'s lasted 7h 30m (Jul 24, 2026).
90-day uptime
Mailchimp Transactional (Mandrill)
SparkPost (Bird)
- No incidents
- Degraded
- Partial outage
- Major outage
- No data
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 →
Recent SparkPost (Bird) incidents
- InformationalOct 30, 2026 · resolved in 22h 2m
Outbound message delivery is delayed/slow for some SparkPost customers (US hosted only)
Affected: SMTP Delivery - USA
- Degraded performanceOct 28, 2026 · resolved in 1h 1m
Outbound message delivery is delayed/slow for some SparkPost customers (US hosted only)
Affected: SMTP Delivery - USA
- Degraded performanceOct 11, 2026 · resolved in 3h 6m
Increased message delays in US and EU due to DNS resolution errors
Affected: SMTP Delivery - USA, SMTP Delivery - EUROPE
- Degraded performanceOct 1, 2026 · resolved in 31m
Affected: SMTP Delivery - USA, SMTP Delivery - EUROPE
- Degraded performanceSep 17, 2026 · resolved in 54m
Outbound message delivery is delayed/slow for some SparkPost customers (US hosted only)
Affected: SMTP Delivery - USA
- Degraded performanceSep 14, 2026 · resolved in 2h 27m
Health Score and Cohort data is delayed
Affected: SparkPost Application - USA, SparkPost Application - EUROPE
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 →