Email Marketing Platforms · reliability comparison
Constant Contact vs Klaviyo: which is more reliable? (2026)
Constant Contact is more reliable than Klaviyo, scoring 90.6 vs 62.2 out of 100. Over the last 90 days Constant Contact reported 4 incidents and Klaviyo reported 13, with effective uptime of 99.92% and 99.26% respectively. Constant Contact resolves incidents faster on average (1h 41m).
Data updated Nov 1, 2026 · How we score
| Metric | Constant Contact | Klaviyo |
|---|---|---|
| Reliability score | 90.6 | 62.2 |
| Rank (email marketing platforms) | #8 | #11 |
| Uptime (90 days) | 99.92% | 99.26% |
| Incidents (90 days) | 4 | 13 |
| Partial / major outages | 1 | 5 |
| Avg time to resolve | 1h 41m | 3h 39m |
| Outages we detected | 0 | 0 |
| Transparency score | 100/100 | 100/100 |
Where Constant Contact and Klaviyo differ
- Klaviyo reported 3.3× as many incidents as Constant Contact over the last 90 days (13 vs 4).
- Klaviyo had 5 partial or major outages, compared with 1 for Constant Contact.
- Constant Contact fixes problems faster: 1h 41m on average, against 3h 39m for Klaviyo (2.2× quicker).
- Constant Contact's longest outage on record lasted 1h 45m (Sep 2, 2026); Klaviyo's lasted 2d 1h (May 5, 2026).
90-day uptime
Constant Contact
Klaviyo
- No incidents
- Degraded
- Partial outage
- Major outage
- No data
Recent Constant Contact incidents
- Degraded performanceOct 1, 2026 · resolved in 57m
Delays in email campaign sending
Affected: Email Campaigns
- Degraded performanceSep 16, 2026 · resolved in 30m
Slow website navigation and email delivery
Affected: Email Campaigns
- Degraded performanceSep 14, 2026 · resolved in 3h 33m
Unable to view partner organization reporting
Affected: Reporting
- Partial outageSep 2, 2026 · resolved in 1h 45m
Affected: Login
Recent Klaviyo incidents
- Partial outageOct 29, 2026 · resolved in 2h 10m
Campaign Sending Delaysofficial update ↗
Affected: Email Sending, Text Message Sending, WhatsApp Sending, Mobile Push Sending
- InformationalOct 28, 2026 · resolved in 23h 43m
Affected: Email Sending, Text Message Sending, WhatsApp Sending, Mobile Push Sending, Processing
- Partial outageOct 22, 2026 · resolved in 14h 47m
Outbound Webhook Delaysofficial update ↗
Affected: Analytics
- Partial outageOct 17, 2026 · resolved in 4h 49m
Flow Sending Delaysofficial update ↗
Affected: Email Sending, Text Message Sending, WhatsApp Sending, Mobile Push Sending, Flow Editor, Processing
- Degraded performanceOct 9, 2026 · resolved in 2h 6m
Analytics Events Processing Delays
Affected: Segments, Profiles, Analytics
- Major outageOct 8, 2026 · resolved in 1h 13m
Login and page loading issuesofficial update ↗
Affected: Klaviyo App
Other email marketing platforms to consider
- Drip · #1 · 100% uptime
- MailerLite · #2 · 100% uptime
- Omnisend · #3 · 100% uptime
- AWeber · #4 · 100% uptime
See the full most reliable email marketing platforms ranking →