The integration step
The team behind isBusinessEmail builds Noium, a B2B product from Tilfortis MB in Lithuania. Noium connects to the tools companies already use, and for most customers that means Google Workspace or Microsoft 365.
We let people sign up with any email address, like most products do. And we kept watching the same thing happen:
- Someone signs up with
@gmail.com,@yahoo.comor@outlook.com. - They get through onboarding.
- They reach Connect your workspace, and it can’t work.
Why it can’t work
It’s not a bug you can fix. The account simply doesn’t have what the integration needs.
| The integration needs | A personal Gmail account | A personal Microsoft account |
|---|---|---|
| An organization with an admin | No Workspace admin console | No Entra ID tenant to administer |
| Organization-wide access | No domain-wide delegation | No admin consent for the organization |
| Shared company content | No Shared Drives | No SharePoint Online, no OneDrive for Business |
| Team collaboration data | n/a | No Teams organization |
From the user’s side, the product looks broken. From ours, they signed up with the wrong account three screens ago and nothing told them.
What it cost
- Stalled onboarding. Users stopped at the most important step.
- Support tickets. “Why can’t I see our SharePoint?” “It says admin approval required, but I don’t have an admin.” “I’m using my Gmail, is that a problem?”
- Restarted accounts. Some users signed up again with their work address, leaving orphaned accounts behind.
- Lost customers. Some just didn’t come back.
None of it was the user’s fault. Browsers autocomplete personal addresses, and “Sign in with Google” or “Sign in with Microsoft” looks the same for personal and work accounts.
What we built
First, a list of free email providers and a warning on the signup form. That helped, and immediately showed the limits of lists: endless regional providers, new disposable domains every day, typos like gmial.com, and custom domains that forward to personal inboxes.
So the check learned to read DNS: MX records, SPF, DMARC, DKIM, SaaS verification tokens. And it learned what we actually needed for onboarding: whether the company runs Google Workspace or Microsoft 365, and for Microsoft, the tenant ID from Microsoft’s public discovery document.
Onboarding changed:
- At signup, a personal address gets a friendly “use your work email to connect your company’s workspace”.
- On the connect screen, the right connector is already selected.
- For admin consent, the link opens the consent screen for the right tenant.
- In sales, Microsoft shops go to the rep who knows Graph and SharePoint.
Why it’s free and public
- Everyone building B2B has this problem. We kept hearing the same story from other founders.
- It gets better with use. More domains and more corrections mean better verdicts for everyone, including us.
- It should be a commodity. “Is this a work email?” is a building block, like “is this address valid?”.
What we won’t do
- Probe mailboxes or accounts. No SMTP checks, no asking Google or Microsoft whether a person exists. We classify domains.
- Store your users’ addresses. Domain plus a keyed hash of the local part, nothing more.
- Pretend to be perfect. We publish our measured accuracy on the stats page, return reasons for every verdict, and give you a
reviewlane for the uncertain middle.
Try it
Type an address in the checker on the home page, or get a free key and follow the quickstart. The long version of this story is on the blog.