Blog
Finding and verifying email addresses
Long, specific and checkable. Every code example was executed and shows what it printed; every claim about a provider is quoted from that provider with the date it was read.
11 September 2026 · 7 min read
How to find someone's email address
Eleven methods, each with the case where it fails — and the step every listicle leaves out, which is finding out whether the address you derived is real.
11 September 2026 · 7 min read
How to validate an email address in Python
What each library actually checks, why check_deliverability does not mean what its name suggests, and the one question none of them can answer.
11 September 2026 · 4 min read
Email validation regex: the pattern and its limits
The pattern worth using, the valid addresses the popular ones reject, and the one question no regular expression can answer.
11 September 2026 · 6 min read
Gmail, Yahoo and Microsoft sender requirements
Every requirement with the provider page it came from, and an honest account of where the 2% and 5% bounce-rate figures actually originate — which is not where you have been told.
11 September 2026 · 5 min read
How to block disposable email addresses
The honest version: a static list is the weakest of four available checks, it is stale within weeks of publication, and the usual implementation blocks customers you wanted.
Definitions live in the glossary, and bounce codes in the SMTP reply code reference.