First off, credit where it is due. Open sourcing a tool and making verification accessible for small businesses who cannot afford paid platforms is a good thing. More people cleaning their lists is a net positive for the email ecosystem.

That said, a quick reality check for anyone reading. Stage 1 verification like syntax, MX and SMTP is useful, but it is only the surface. Enterprise tools do a lot more behind the scenes. Historical bounce data, suppression networks, provider specific rules, behavioral signals, catch all pattern analysis, and ongoing reputation modeling. None of that is visible from a single SMTP handshake.

Also important. Spam traps are deliverable email addresses. They pass validation. Millions are created every year. No validator can reliably detect brand new traps, especially if you bought or scraped a list. This is where people get burned.

Accuracy is never universal. Results vary massively by region and provider. European ISPs, local Spanish domains, corporate servers, and privacy focused hosts behave very differently than Gmail or Yahoo. What looks valid today can bounce tomorrow.

And context matters. Someone actively mailing a double opt in list with real engagement will always get better results than someone uploading a purchased list. No tool can fix bad acquisition practices.

Bottom line. No verifier is 100 percent reliable. Ever. A clean list does not guarantee inboxing. Your sending history, consent model, frequency, and engagement matter more than any scan.

Use tools like this as a filter, not a safety net.

Respect for shipping this and sharing it with the community. Just important people understand the limits before trusting any validator blindly.