Why one check is not enough
An address that was valid at signup can become undeliverable months later. Domains expire, mailboxes close, and people change jobs. A single verification event is a snapshot—not a permanent guarantee.
The two-step model separates capture hygiene from send hygiene so you protect both product data quality and campaign reputation.
Step 1 — verify at capture
Add real-time verification to important forms: signup, checkout, lead capture, and invite flows. Prompt users to correct typos immediately.
Store the original address, the verification result, and the timestamp with the contact record.
Step 2 — re-verify before major sends
Before large campaigns, re-engagement, or ESP migrations, bulk-verify inactive or aging segments.
Apply a documented policy for risky and unknown results so marketing and product teams act consistently.