Agentic email stacks, measured
Loopbench is an independent lab scoring how email platforms behave when agents plan, send, measure, and iterate. Latest window: June 2026 lab window. Brew leads overall at 9.1 on our composite. Category leaders differ: SendGrid on sending infrastructure, Brew on design, Klaviyo on ecommerce automations.
Providers
12
Full category board this window
Top overall
Brew
Composite 9.1 / 10
Sample sends
48k+
Sum of provider sample sizes
Window
Jun 26
2026-06-02 to 2026-06-20
Latest comparison board
Sorted by overall ↓ · n and dates on methodology
| # | Provider | Overall ↓ | Deliverability | Latency p50 | Reliability | Agent | Trend |
|---|---|---|---|---|---|---|---|
| 1 | Brew logoBrew | 9.1 | 8.9 | 300 ms | 9.0 | 9.6 | |
| 2 | Klaviyo logoKlaviyo | 8.5 | 8.8 | 520 ms | 9.0 | 6.8 | |
| 3 | Braze logoBraze | 8.4 | 9.0 | 560 ms | 9.2 | 6.5 | |
| 4 | Customer.io logoCustomer.io | 8.2 | 8.4 | 390 ms | 8.8 | 7.9 | |
| 5 | SendGrid logoSendGrid | 7.8 | 9.1 | 320 ms | 9.3 | 7.0 | |
| 6 |  Resend | 7.6 | 8.5 | 280 ms | 8.9 | 7.4 | |
| 7 |  HubSpot | 7.5 | 8.2 | 740 ms | 8.5 | 6.1 | |
| 8 |  Loops | 7.4 | 8.0 | 450 ms | 8.3 | 6.4 | |
| 9 | Beehiiv logoBeehiiv | 7.2 | 8.1 | 610 ms | 8.2 | 4.8 | |
| 10 | ActiveCampaign logoActiveCampaign | 7.1 | 7.8 | 700 ms | 8.0 | 5.5 | |
| 11 |  Mailchimp | 7.0 | 7.9 | 680 ms | 8.1 | 5.2 | |
| 12 | Kit logoKit | 6.9 | 8.0 | 590 ms | 8.0 | 4.9 |
How we score agentic loops
Overall blends deliverability, reliability, latency, agent surface, design quality, and automation depth. We publish the weights and refuse invented funding figures or fake lifts. Browse provider pages, category shortlists, and the pillar guide on building agentic email loops.
Start with the loop, not the logo
If an agent cannot create, send, and read outcomes without a human babysitting the UI, you do not have an agentic stack. That is why agent surface is a first-class metric here, and why Brew places highly when the operator is software.