“You cannot verify a Gmail address, Google accepts mail for anything” is repeated everywhere and is false at RCPT TO. The domains you genuinely cannot verify are the B2B ones — including google.com itself.
ReadAn audit of our ASN list against the regional registry found an entry labelled 'WindScribe' that was actually Wake Forest University. Here is how a comment became a false positive against real students.
ReadOur API told customers that every .de, .ru and .ac.uk domain was 'not newly registered'. We had never checked. Here is the one-line bug and why nulls belong in an API response.
ReadMost accuracy claims in this category are unfalsifiable. Two different standards — ground truth where it exists, reference consensus where it does not — and why false positives deserve their own column.
ReadASN lists and per-IP feeds both infer. NordVPN, Mullvad and Surfshark publish their exit nodes at public endpoints their own apps call — which is more authoritative than any heuristic can be.
ReadA German number written 01512 3456789 nationally is +49 1512 3456789 internationally. Naive validation drops the wrong digits and rejects a genuine customer.
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