Who we are
isBusinessEmail is built and run by Tilfortis MB, a small software company in Lithuania. We also build Noium, a B2B product that connects to companies’ Google Workspace and Microsoft 365, which is where this started. Read why.
We use isBusinessEmail in production for our own signups, so we feel its mistakes first.
What we do
A free public API and website that tells B2B products:
- whether a signup is a work email (on the company’s own domain) or personal (on a shared-domain provider)
- whether it’s disposable, a relay or blocked
- whether the company runs Google Workspace or Microsoft 365, with the Microsoft tenant ID
with an allow / review / block recommendation and the reasons behind it.
How we work
- Domains, not people. We don’t probe mailboxes or ask providers about individuals.
- Minimal data. We never store the full addresses you check; see Privacy and data.
- EU-hosted data. Our database runs on Hetzner in the EU; the API runs on Cloudflare’s edge.
- Measured, not promised. Engine changes are tested against a labeled evaluation set in CI, and the accuracy is published on /stats.
- Explainable. Every verdict comes with reason codes.
- Corrections by people. Feedback goes to a review queue, never straight into the lists.
Company details
| Legal name | Tilfortis MB (a Lithuanian small partnership, mažoji bendrija) |
| Country | Lithuania |
| General contact | hello@isbusinessemail.com |
| Privacy | privacy@isbusinessemail.com |
| Security | security@isbusinessemail.com |