To identify a free email provider, compare the address domain with a maintained consumer-domain set and then inspect its MX provider. Do not rely on MX alone. A company can use Google Workspace or Microsoft 365 on its own domain without being a free personal address.
What counts as a free provider?
A free provider gives individuals a mailbox on a shared public domain, such as Gmail, Outlook.com, Yahoo, AOL, iCloud, or Proton Mail. A business address normally uses an organization-controlled domain even when Google or Microsoft hosts it.
| Address | MX clue | Classification |
|---|---|---|
person@gmail.com | Consumer free-provider domain | |
person@outlook.com | Microsoft | Consumer free-provider domain |
person@company.example | Microsoft 365 | Business domain hosted by Microsoft |
person@studio.example | Google Workspace | Business domain hosted by Google |
Free provider is not disposable
A personal Gmail address can remain active for years. A disposable address is intended for short-lived use or appears in maintained throwaway-domain data. Blocking both categories discards legitimate users.
Keep fields such as free provider and disposable separate. Your product can then ask for a work address only where there is a real reason.
Visible domain and MX signals
Exact matching of the part after @ is the first signal for known consumer domains. Mailthentic maintains this data in the application instead of publishing a supposedly complete list here. Avoid substring rules and normalize internationalized domains.
An MX lookup can identify the hosting platform. It helps explain verification behavior, but it does not decide personal versus business by itself. A gateway can also hide the final provider.
Mailthentic's classification path
- Normalize the domain and compare it with the maintained consumer set.
- Resolve MX hosts and match maintained provider patterns.
- Keep provider identity separate from disposable and role-based signals.
- Use a safe verification mode for providers that hide recipient existence.
Practical uses
- Ask for a work address in a B2B form while allowing correction.
- Route personal and business leads to different workflows.
- Prevent a business email finder from guessing addresses on public domains.
- Measure signup mix without rejecting valid users.
Limits, privacy, and ethical use
Classification can be wrong when a domain changes hosts or is missing from maintained data. Give users a correction path. Do not infer employment, income, identity, or trustworthiness from a provider category.
Use the single-address checker, review the API workflow, and keep disposable logic separate with the disposable email guide.
Inspect provider signals
Check one address or run a domain-level MX lookup.
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