Blog/ESP

Integrating MailAdx with Klaviyo

Flow triggers and custom properties for dynamic ad slots.

MT

MailAdx Team

2026-03-14 · 9 min read

Connecting MailAdx to Klaviyo

Klaviyo is a popular ESP for e-commerce and DTC brands, with powerful audience segmentation and flow-based automation. Integrating MailAdx with Klaviyo uses the same open-time pattern as Mailchimp: add a profile property for the email hash, paste the ad tag, and MailAdx runs the waterfall when subscribers open — for both campaigns and flows.

Step 1: Add the email_sha256 profile property

In Klaviyo, create a profile property email_sha256 containing the SHA-256 hex hash of each subscriber's lowercase email. Populate it via CSV import, API, or a flow action before sends go out.

Step 2: Paste the ad tag

In Klaviyo's template editor, add a Custom HTML block where the ad should appear. Paste the ad tag from Dashboard → Ad Units, using {{ person.email_sha256 | default:'' }} as the hash parameter in the display and click URLs.

Step 3: Flows and campaigns

The same ad tag works in one-time campaigns and automated flows without changes. Because the ad decision runs at open time, subscribers who open a flow email days after it was sent still receive a current, relevant ad — not a stale creative frozen at send time.

Conclusion

Once configured, open-time ad serving works automatically for all Klaviyo campaigns and flows. See the full guide at Klaviyo integration docs, all ESP integrations, or contact our team for integration support.

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MT

MailAdx Team

MailAdx Team

2026-03-14·9 min read

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