Customer.io
#1 in Transactional Email1
Products on G2
990
Total reviews
4.4
Avg. star rating
- Customer.io ranks #1 in Transactional Email.
- Reviews across Customer.io's portfolio grew 7.1% quarter-over-quarter.
- Customer.io's 1 product span 7 categories on G2.
- Small Business is the largest segment among reviewers, at 59.3%.
Traffic & LLM citations
Source: G2 review data
Winning from
Losing to
Key stats
+7.1%
#1
7
Small Business
2012
574
Portland, OR
Adoption by company size
| Segment | Share of reviews |
|---|---|
| Small Business | 59.3% |
| Mid-Market | 37.4% |
| Enterprise | 3.2% |
Quarterly history
| Quarter | Total reviews | Avg. rating |
|---|---|---|
| 2024 Q4 | 44 | 4.5 |
| 2025 Q1 | 85 | 4.3 |
| 2025 Q2 | 53 | 4.4 |
| 2025 Q3 | 51 | 4.5 |
| 2025 Q4 | 68 | 4.2 |
| 2026 Q1 | 72 | 4.4 |
| 2026 Q2 | 113 | 4.2 |
| 2026 Q3 | 121 | 4.2 |