Connect MailAdx with your ESP
MailAdx connects to every major email service provider via merge tags and ad tags. Switch ESPs without rebuilding your ad stack.
Works with what you already use
The MailAdx philosophy is to fit into your existing workflow, not replace it. We don't care which ESP you use. Copy the ad tag from your Dashboard, add an email-hash merge field, and paste into your template — the same two-line HTML block works across Mailchimp, Klaviyo, Beehiiv, and custom pipelines. Your template stays in your ESP, your subscriber list stays in your ESP, and your send schedule stays in your ESP. MailAdx runs the auction when subscribers open.
- No migration required — works alongside your existing setup
- Pre-built connectors maintained by the MailAdx team
- New ESP connectors released monthly
Zero-downtime integration process
Connecting MailAdx to your ESP follows a documented three-step process: add the EMAIL_SHA256 merge field, paste the ad tag from Dashboard → Ad Units into your template, and send a test campaign. Open the test email to verify the ad loads and an impression appears in your Publisher Portal. The entire process typically takes under two hours. Our onboarding team is available on live chat throughout.
- Step-by-step integration guides for every supported ESP
- Live chat support during onboarding
- No webhooks or send pipeline changes required
Everything you need
All the features, none of the complexity.
22+ ESP connectors
Pre-built ad tag guides for Mailchimp, Klaviyo, Beehiiv, SendGrid, Mailmodo, ActiveCampaign, and more.
Merge tag integration
Substitute each subscriber's SHA-256 email hash at send — MailAdx runs the auction when they open.
Custom SMTP pipeline
Self-hosted email pipelines can embed the same display URL pattern with per-subscriber hash substitution.
Dual-ESP support
Running two ESPs simultaneously? MailAdx handles multi-ESP routing with a single account.
Copy-paste ad tags
Dashboard generates ready-to-paste HTML ad blocks for every placement — no code required.
Sandbox testing
Test your ESP integration against our sandbox before going live — no risk to real sends.
“We switched from Mailchimp to Beehiiv last year and our MailAdx integration survived the transition untouched. That was the biggest relief.”
Connect your ESP and go live in minutes
Pre-built adapters for 22+ ESPs. Most teams complete their integration in under two hours — with our onboarding team on live chat throughout.