TL;DR
- Two jobs: check addresses as they arrive (signup, checkout) and clean the list you already have.
- At checkout, block only undeliverable and let unknown through, so a slow mail server never costs you a sale.
- No Shopify or WooCommerce app yet. Use the API from your own code, and bulk upload for the list.
Where store email lists go wrong
Store lists collect addresses from checkout forms, popups, account signups and discount-code offers. Some of those addresses are typos, and some are throwaway addresses made to get a code. People also abandon accounts over time. The result is a list where a share of addresses can't receive mail. We don't have store-specific statistics, so we won't quote one.
The harm is concrete. Order confirmations to a mistyped address never arrive, which becomes a support ticket. Marketing sends to dead addresses raise your bounce rate. And if your platform prices by contact count, you pay to store contacts that can't be reached. See bounce thresholds for what mailbox providers and tools tolerate.
Workflow: check at the door, clean the list
- At signup or checkout, call the API from your backend with the address. If the state is undeliverable (for example invalid_domain from a typo like a nonexistent domain), ask the customer to correct it. If it is disposable, decide whether you accept it for a discount signup. Everything else, including unknown, goes through. The API is live, keys on request via contact.
- Clean the existing list in bulk. Export subscribers as CSV, upload to Mail Exchange, and remove undeliverable and disposable rows before your next campaign.
- Re-clean on a schedule, for example before big sales sends. See how often to verify.
Which results to act on
| Result | At checkout or signup | In a list clean |
|---|---|---|
| Deliverable | Accept. | Keep. |
| Risky: catch-all | Accept. | Keep; watch bounces. |
| Risky: role | Accept (small business buyers use info@). | Keep for transactional, review for marketing. |
| Risky: disposable | Your call: accept or ask for another. | Remove from marketing. |
| Undeliverable | Ask the customer to fix it. | Remove. |
| Unknown | Accept. | Retry later. Refunded. |
What it costs
$29 for 5,000 checks; credits never expire, which suits seasonal peaks. Unknowns and duplicates are refunded. See pricing.