A SaaS product depends on the email address for activation, recovery, billing and lifecycle communication. A typo at signup can create a support issue before the user reaches the product. Verification helps identify the problem while it is still easy to correct.
Where to verify
- Registration and invited-user flows.
- Changes to the primary account address.
- High-value lead or trial forms.
- Imports from partners or a legacy product.
- Before lifecycle campaigns to older trial users.
Do not turn uncertainty into a hostile signup
A temporary mail-server response or catch-all domain is not the same as an invalid address. Reserve hard blocking for strong outcomes such as malformed structure, disposable addresses when prohibited by policy, or a confirmed undeliverable mailbox. Offer a correction path and log the reason shown to the user.
Fast synchronous response
The ListCleaner single-email endpoint returns a compact JSON response with the request ID, normalized address and status. It first uses internal knowledge, then performs the external verification step only when needed. No verification email is sent to the user.
Review the interactive API documentation for examples in PHP, Python, Node.js, Ruby, Go, Java, C# and other languages.
Protect your next signup flow
Create an account, use the included credits and review the classifications before committing a larger database.