ZapBounce and Justuno
Justuno targets offers by visitor behavior and traffic source, which makes it unusual among popup tools: it already thinks in segments.
A verification verdict fits that model directly. It becomes another attribute the targeting can read rather than only a cleanup step.
Sophisticated targeting fed by unverified capture
Justuno can target an offer by referrer, cart value and behavior, and then collect an address nobody checks. The precision of the targeting is wasted on a subscriber who cannot receive anything.
Because Justuno's offers are often high value, such as a meaningful discount, the incentive to supply a throwaway address is correspondingly higher.
The verdict feeding back into segmentation closes the loop: a returning visitor known to have given a bad address can be shown a different offer.
How the data moves
Verify at capture through a webhook
Between the Justuno submission and whatever receives the subscriber.
Feed the verdict back as a visitor attribute
Justuno can target on custom attributes, so a returning visitor's previous verdict can change what they are shown.
Segment by traffic source and verdict together
Which sources produce addresses that do not exist is an acquisition insight rather than a list-hygiene one.
Show the typo suggestion in the promotion
Justuno's designer allows custom fields and messaging, so the correction can appear in the offer itself.
Setting it up
- Route Justuno submissions through a webhook handler that verifies before forwarding.
- Store the verdict with the subscriber in your email platform.
- Push the verdict back as a Justuno visitor attribute where your setup allows.
- Build a promotion variant for visitors whose previous address failed.
- Report invalid rate by traffic source, not only overall.
- Show the typo suggestion inside the promotion rather than after submission.
Justuno: common questions
Can the verdict change what a visitor sees?
Where Justuno recognizes them as returning, yes, through a custom attribute. It will not work across devices.
Which traffic sources produce bad addresses?
Measure it. Paid social usually worse than search, but your own numbers are what matter.
Should a high-value offer verify more strictly?
Verify the same way and segment differently. Withholding an offer over a verdict costs orders.
A 15% code and the addresses it attracts
Say your store shows a 15% welcome offer to new visitors and collects 2,000 addresses a month through Justuno. You route submissions through a handler that checks each one, and the first month's split is 1,640 valid, 90 invalid, 120 catch-all or unknown, and 150 more that carry the disposable flag.
Break the 240 invalid and disposable-flagged rows down by traffic source and the picture changes. Suppose paid social sent 700 of the 2,000 signups but 170 of those 240. That's a 24% bad-address rate on paid social against about 5% on everything else. Your real cost per subscriber on that channel is about a third higher than the ad platform reports, because it counts a throwaway address as a lead.
That finding belongs with whoever buys the ads. Cleaning the list afterwards doesn't recover the spend.
Show the code on screen, or send it by email
How you deliver the discount decides how much a fake address costs you. If the code appears on screen after submit, a visitor can type anything, take the code and leave. If the code arrives by email, a made-up address gets nothing, and most of the incentive to invent one disappears. Disposable inboxes still receive it, which is why the disposable flag matters more on email-delivered offers.
Emailing the code has a cost too. Some real buyers won't wait for a message, and a welcome email that lands in a promotions tab can lose the sale. If your Justuno setup lets a custom script decide what the thank-you step shows, there's a middle path: show the code on screen when the check comes back valid, and email it for everything else. Nobody is refused, and the unverifiable rows prove themselves by opening the message.
Run the check on your server, in the handler that receives the submission. An API key placed in front-end code is public, so the call can't run from the promotion's own script.
Check a Justuno export today
100 free checks a month, no card. Unknown results and duplicates are never billed.