Kickbox is known for email verification: helping senders keep lists deliverable and protect their sender reputation, via an API and integrations with email platforms.
isBusinessEmail is built for a different moment: the signup form of a B2B product, where the question is whether the person is signing up with their company’s domain and whether that company can use your Google or Microsoft integrations.
What isBusinessEmail does differently
| isBusinessEmail | |
|---|---|
| Question | Work email or personal? Disposable, relay, blocked? |
| Approach | Domain classification: curated lists + DNS signals (MX, SPF, DMARC, DKIM, verification tokens) |
| Mailbox probing | None. We never test whether a specific mailbox exists. |
| Workspace detection | Google Workspace / Microsoft 365, with Microsoft tenant ID and federation |
| Decision | allow / review / block with reason codes |
| Price | Free with fair-use limits |
For Kickbox’s current capabilities and pricing, check their site.
When a verifier is the better tool
- Cleaning a mailing list before a campaign
- Reducing bounces and protecting sender reputation
- Answering “does this mailbox accept mail?”
When isBusinessEmail is the better tool
- Requiring or preferring work emails at signup
- Lead qualification and routing by company domain and suite
- Pre-selecting the right connector during onboarding
- A privacy-friendly check that doesn’t contact the user’s mail server
Why we don’t do mailbox checks
Probing mailboxes means talking to the recipient’s mail server (or a provider’s login system) about a specific person. Catch-all domains, greylisting and rate limits make the answers noisy, and it reveals that someone signed up somewhere. For our question, whether the domain belongs to a company, the domain’s own DNS is the better evidence. More in Workspace detection.
Use them together
isBusinessEmail at signup and for routing; a deliverability verifier before you email old or imported lists.