Transactional Email APIs · reliability comparison

Mailchimp Transactional (Mandrill) vs Resend: which is more reliable? (2026)

Mailchimp Transactional (Mandrill) is more reliable than Resend, scoring 90.6 vs 60.5 out of 100. Over the last 90 days Mailchimp Transactional (Mandrill) reported 3 incidents and Resend reported 23, with effective uptime of 99.93% and 99.39% respectively. Mailchimp Transactional (Mandrill) resolves incidents faster on average (3h 4m).

Data updated Nov 2, 2026 · How we score

Mailchimp Transactional (Mandrill)

90.6/100

Operational

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Resend

60.5/100

Operational

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VS
MetricMailchimp Transactional (Mandrill)Resend
Reliability score90.660.5
Rank (transactional email APIs)#5#11
Uptime (90 days)99.93%99.39%
Incidents (90 days)323
Partial / major outages04
Avg time to resolve3h 4m3h 39m
Outages we detected00
Transparency score100/100100/100

Where Mailchimp Transactional (Mandrill) and Resend differ

  • Resend reported 7.7× as many incidents as Mailchimp Transactional (Mandrill) over the last 90 days (23 vs 3).
  • Resend had 4 partial or major outages, compared with 0 for Mailchimp Transactional (Mandrill).
  • Mailchimp Transactional (Mandrill) fixes problems faster: 3h 4m on average, against 3h 39m for Resend.
  • Mailchimp Transactional (Mandrill)'s longest incident on record lasted 4h 26m (Sep 15, 2026); Resend's lasted 2h 39m (Aug 8, 2026).

90-day uptime

Mailchimp Transactional (Mandrill)

Aug 5, 2026 – Aug 31, 2026: no incidentsSep 1, 2026: 97.41% uptime, 1 incident (Degraded performance)Sep 2, 2026 – Sep 14, 2026: no incidentsSep 15, 2026: 97.22% uptime, 1 incident (Degraded performance)Sep 16, 2026: no incidentsSep 17, 2026: 99.69% uptime, 1 incident (Degraded performance)Sep 18, 2026: 99.90% uptime, 1 incident (Degraded performance)Sep 19, 2026 – Nov 2, 2026: no incidents
90 days ago99.936% average daily uptimeToday

Resend

Aug 5, 2026 – Aug 6, 2026: no incidentsAug 7, 2026: 99.74% uptime, 1 incident (Degraded performance)Aug 8, 2026: 94.47% uptime, 1 incident (Partial outage)Aug 9, 2026 – Aug 12, 2026: no incidentsAug 13, 2026: 99.54% uptime, 1 incident (Partial outage)Aug 14, 2026 – Aug 15, 2026: no incidentsAug 16, 2026: 100% uptime, 1 incident (Degraded performance)Aug 17, 2026: no incidentsAug 18, 2026: 97.42% uptime, 1 incident (Degraded performance)Aug 19, 2026: 93.73% uptime, 1 incident (Degraded performance)Aug 20, 2026: 99.75% uptime, 1 incident (Degraded performance)Aug 21, 2026 – Sep 2, 2026: no incidentsSep 3, 2026: 99.59% uptime, 1 incident (Degraded performance)Sep 4, 2026: 99.66% uptime, 1 incident (Degraded performance)Sep 5, 2026 – Sep 10, 2026: no incidentsSep 11, 2026: 99.93% uptime, 1 incident (Major outage)Sep 12, 2026 – Sep 14, 2026: no incidentsSep 15, 2026: 97.23% uptime, 1 incident (Partial outage)Sep 16, 2026: 99.94% uptime, 2 incidents (Degraded performance)Sep 17, 2026: no incidentsSep 18, 2026: 96.52% uptime, 2 incidents (Degraded performance)Sep 19, 2026: 85.00% uptime, 1 incident (Degraded performance)Sep 20, 2026: 88.47% uptime, 1 incident (Degraded performance)Sep 21, 2026: no incidentsSep 22, 2026: 99.37% uptime, 1 incident (Degraded performance)Sep 23, 2026: no incidentsSep 24, 2026: 99.46% uptime, 1 incident (Degraded performance)Sep 25, 2026: no incidentsSep 26, 2026: 98.26% uptime, 1 incident (Degraded performance)Sep 27, 2026 – Sep 30, 2026: no incidentsOct 1, 2026: 99.45% uptime, 1 incident (Degraded performance)Oct 2, 2026 – Oct 8, 2026: no incidentsOct 9, 2026: 99.76% uptime, 1 incident (Degraded performance)Oct 10, 2026: 99.27% uptime, 1 incident (Degraded performance)Oct 11, 2026 – Oct 22, 2026: no incidentsOct 23, 2026: 99.48% uptime, 1 incident (Degraded performance)Oct 24, 2026 – Oct 25, 2026: no incidentsOct 26, 2026: 99.76% uptime, 1 incident (Degraded performance)Oct 27, 2026 – Nov 2, 2026: no incidents
90 days ago99.398% average daily uptimeToday

Recent Mailchimp Transactional (Mandrill) incidents

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Recent Resend incidents

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