Email Validator
Optional MX lookup connects directly from your browser
Why: Email syntax checks are local. The optional MX diagnostic queries the selected DNS-over-HTTPS resolver.
Data sent:
- The email domain only, MX queries and fallback A/AAAA queries; the mailbox name is not sent
Data handling: Cloudflare or Google receives the domain query and may retain it under its own policies. This diagnostic does not contact the mailbox or prove delivery.
This app does not log, trace or save request/response payloads or uploaded files on its server. External APIs and storage providers apply their own retention policies; this app cannot delete their copies.
Audit the source: src/lib/email-mx.ts
Single Email
Valid syntaxDomain: example.comLocal: user
Bulk Validate
Allow disposable
Allow role
Total: 4Valid: 3Invalid: 1
| Status | Flags | |
|---|---|---|
| alice@example.com | Valid | |
| bob@mailinator.com | Valid | disposable |
| admin@company.io | Valid | role |
| broken@ | Invalid | Invalid syntax |
Email domain MX diagnostics
Only the domain is sent directly to the selected public DNS-over-HTTPS resolver when you click. The email address and local part stay in your browser. DNS records cannot confirm whether a mailbox exists.
Standards, sources and review dates
- Null MX · RFC 7505 · June 2015 · Reviewed
Distinguishes explicit no-mail domains, ordinary MX, implicit A/AAAA fallback, NXDOMAIN and lookup failure. DNS does not establish mailbox deliverability. Review interval: 180 days.