September 1, 2026 
2 min read 
Personalized email content is most useful when it appears quickly at the moment a recipient opens the message.
That is exactly what Clerk.io Email Embeds are built for: you send campaigns from your own email platform, while Clerk.io selects and delivers personalized product content when each email is opened.
We have rebuilt the image-delivery layer behind Email Embeds to make that experience significantly faster and give large campaigns much more capacity.
Personalized images, delivered at open
Email Embeds let you send your own emails while Clerk.io delivers the product content when a recipient opens them.
Because the content is loaded at open, shoppers can see personalized product images based on the latest available data—not simply a static selection prepared when the campaign was sent.
Large sends can generate many opens within a short period. The image-delivery layer therefore needs to respond quickly and handle sudden peaks without slowing the experience down.
A faster image-delivery foundation
The completely rewritten image CDN behind Email Embeds has produced substantial performance improvements under real traffic:
- Over 97% lower median latency, with most requests completing in under 1 millisecond
- 90% lower P95 latency, improving performance across slower requests too
- 3–4× the throughput, allowing more images to be delivered at once
- Over 90% less memory usage
- Around 95% less CPU usage
The result is a much more efficient foundation for delivering personalized product images at scale.
More headroom when a campaign lands
When a large campaign reaches thousands of inboxes, image requests can arrive in a concentrated burst as recipients begin opening the email.
Higher throughput gives Email Embeds more room to handle those peaks. Lower latency helps product images appear sooner, while the large reduction in resource usage allows the service to manage demand more efficiently.
For merchants, that means greater confidence that personalized content can keep up with a successful send. For recipients, it means a faster and more reliable experience when they open the email.
Your workflow stays the same
The improvement happens behind the scenes.
You can continue designing and sending campaigns from your existing email platform. Clerk.io Email Embeds still select and deliver the personalized product content when the email is opened—now through a significantly faster image-delivery foundation.
The outcome is simple: relevant product images that appear faster, plus more capacity for the moments when a large campaign drives a surge of opens.
