Transactional Email APIs · reliability comparison
Resend vs SparkPost (Bird): which is more reliable? (2026)
SparkPost (Bird) is more reliable than Resend, scoring 87.7 vs 60.5 out of 100. Over the last 90 days Resend reported 23 incidents and SparkPost (Bird) reported 8, with effective uptime of 99.39% and 99.90% respectively. SparkPost (Bird) resolves incidents faster on average (2h).
Data updated Nov 1, 2026 · How we score
| Metric | Resend | SparkPost (Bird) |
|---|---|---|
| Reliability score | 60.5 | 87.7 |
| Rank (transactional email APIs) | #10 | #5 |
| Uptime (90 days) | 99.39% | 99.90% |
| Incidents (90 days) | 23 | 8 |
| Partial / major outages | 4 | 0 |
| Avg time to resolve | 3h 39m | 2h |
| Outages we detected | 0 | 0 |
| Transparency score | 100/100 | 100/100 |
Where Resend and SparkPost (Bird) differ
- Resend reported 2.9× as many incidents as SparkPost (Bird) over the last 90 days (23 vs 8).
- Resend had 4 partial or major outages, compared with 0 for SparkPost (Bird).
- SparkPost (Bird) fixes problems faster: 2h on average, against 3h 39m for Resend.
- Resend's longest outage on record lasted 2h 39m (Aug 8, 2026); SparkPost (Bird)'s lasted 7h 30m (Jul 24, 2026).
90-day uptime
Resend
SparkPost (Bird)
- No incidents
- Degraded
- Partial outage
- Major outage
- No data
Recent Resend incidents
- Degraded performanceOct 26, 2026 · resolved in 23m
Affected: Email Events
- Degraded performanceOct 23, 2026 · resolved in 49m
Intermittent latency spikes on our emails API
Affected: Single Email, Broadcast Emails, Batch Emails, Scheduled Emails
- Degraded performanceOct 10, 2026 · resolved in 1h 9m
Delayed new team provisioning and contact webhook delivery
Affected: Webhooks, Dashboard, General API
- Degraded performanceOct 9, 2026 · resolved in 23m
Delayed new team provisioning and contact webhook delivery
Affected: Dashboard, General API, Webhooks
- Degraded performanceOct 1, 2026 · resolved in 52m
- Degraded performanceSep 26, 2026 · resolved in 2h 46m
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 →