ZeroBounce alternative for work-email detection

ZeroBounce is best known for email validation and list cleaning: checking whether addresses are deliverable before you send campaigns, plus related deliverability tooling. If that’s your job, it’s a reasonable place to look.

isBusinessEmail answers a different question: is this a work email, and what does the company run? We built it for B2B signup forms and onboarding, not for list cleaning.

What isBusinessEmail does differently

	isBusinessEmail
Main question	Is the address on a company’s own domain or a shared provider? Disposable, relay, blocked?
Google Workspace / Microsoft 365	Detected per domain, with Microsoft tenant ID, region and federation (Okta, ADFS…)
Mailbox probing	None. No SMTP `RCPT` checks, no provider account lookups. We classify the domain.
Output	`category`, `recommendation` (`allow`/`review`/`block`) under a policy you choose, plus reason codes
Price	Free, with fair-use limits
Data	Never stores full addresses: domain + a keyed hash of the local part. EU database.

For ZeroBounce’s current features and pricing, check their site.

Choose a deliverability verifier when…

You’re about to send to a list and want to remove bounces, spam traps and inactive addresses.
You need “does this exact mailbox exist?” for a marketing send.

Choose isBusinessEmail when…

You want to require or prefer work emails at signup.
You need to know whether a company runs Google Workspace or Microsoft 365 to route onboarding or sales.
You want an explainable allow/review/block decision you can show in your UI.
You prefer an approach that doesn’t touch individual mailboxes.

Using both

They fit together well: isBusinessEmail at signup (is this a company? which suite?), and a deliverability verifier before bulk sends to old lists. Different questions, different moments.

Try it

curl -sG https://api.isbusinessemail.com/v1/check \
  --data-urlencode "email=workspace@test.isbusinessemail.com"

No key needed for test addresses. Get a free key for real ones.