Lead generation
Paying for leads that bounce, or for a form filled in by a bot, is a direct and measurable waste.
What the problem actually is
Lead-gen economics are unforgiving: you pay per lead whether or not it is real. Bot-filled forms, mistyped emails and disposable addresses all bill the same as a genuine prospect, then poison sender reputation when the follow-up bounces. The cost is doubled — wasted spend, then deliverability damage that makes the good leads harder to reach.
Signals that carry the weight here
A hard bounce costs you twice: the lead and a small amount of sender reputation. Catching it at submission is far cheaper than after a send.
gmial.com is a real person who mistyped, not a fraudster. Suggesting the correction recovers a lead you paid for instead of discarding it.
A number that was never allocated cannot be dialled, so it should never enter a dialler queue or an SDR's day.
Where to start
strictness=1 (balanced) — Balanced, and use the suggestion rather than the verdict where a typo is detected — the goal is recovering leads, not rejecting them.
A defensible starting point, not a guarantee. Strictness moves the verdict thresholds only; the risk score itself never changes, so you can re-tune without re-scoring anything.
The call
curl -X POST "https://www.layercall.com/v1/score/user" \ -H "X-Api-Key: YOUR_KEY" \ -H "Content-Type: application/json" \ -d '{"email":"$EMAIL","phone":"$PHONE"}'
1,000 lookups a month free, no card. Get an API key.
Questions
Will you tell me if a mailbox actually exists?
Honestly, or not at all. mailbox_exists is null rather than a guess, and today it is null for every address: the SMTP probe needs a host permitting outbound port 25, which the platform the API runs on blocks outright. Two things stay true whenever it does ship — a catch-all domain accepts mail for addresses that do not exist, so nobody can verify those at any price, and a server that defers the question gets a null from us rather than a reassuring yes.