Blog

Technical and practical guides on verifying email, IP and phone. Written from the engine running in production.

October 11, 2026·8 min read·email, SMTP, technical, verification
SMTP probing: how to know if an email exists without sending anything
A step-by-step explanation of the SMTP handshake we use to verify deliverability without generating bounces, with the common traps (catch-all, Yahoo, greylisting) and how we handle them.
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October 11, 2026·7 min read·phone, HLR, verification, telecom
HLR lookup vs local validation: when to spend 6 credits instead of 1
Two phone verification tiers solve different problems. We explain what each returns, how much they cost and when in the funnel each tier makes sense.
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