DQE validates email addresses by checking whether the submitted value is technically valid and whether enough information is available to assess the domain and mailbox with confidence.
What DQE checks
- email address format;
- domain syntax;
- domain existence and configuration;
- availability of validation information for the domain;
- mailbox-level indicators when they are available;
- risk or uncertainty signals depending on the validation context.
Why results may vary
Email validation depends on the information available at the time of the request. Some domains provide enough signals to validate an address confidently, while others apply private or restrictive policies that limit the information available.
Private and restrictive domains
Most standard email domains can be checked by DQE. However, some private domains apply their own policies and may limit validation results. In these cases, DQE may return a conservative status instead of confirming an address that cannot be reliably verified.
Best practices
- Submit clean email addresses without spaces or hidden characters.
- Validate the full address, not only the domain.
- Review the returned status together with your business rules.
- Use consistent environments and licences when comparing results.