Email Deliverability Scoring API
A pass/fail verdict throws away nuance. Get a 0-100 score that blends every check, so you set the risk threshold that fits your funnel.
What Mailbeam checks
Every verification runs 7 checks in parallel and returns a structured result in under 100ms.
One number, every signal
Syntax, MX, SMTP, disposable, role, free-provider, and catch-all results roll up into a single 0-100 score you can act on directly.
Threshold in your code, not ours
Block below 40, review 40-70, accept above 70 — or pick your own cutoffs. The score gives you a dial instead of a switch.
Component checks stay visible
The individual check results ship alongside the score, so you can explain or override any decision.
Stable and deterministic
The same address returns the same score, making the number safe to store, compare, and trend over time.
Catch-all aware
Catch-all domains, where SMTP can't confirm a mailbox, are scored as measured risk rather than a false 'deliverable'.
Built for automation
A numeric score is trivial to use in lead-routing rules, warehouse models, and reactivation cutoffs.
How it works
POST the address
Send the email to /v1/verify; all component checks run in parallel.
Signals are weighted
Each check contributes to the score by its predictive weight — a failed MX weighs far more than a role flag.
Score is returned with the breakdown
The JSON includes score (0-100), status, and every individual check so nothing is hidden behind the number.
You apply thresholds
Branch in code on the score to accept, review, or reject — and log it for later analysis.
Integrate in minutes
const res = await fetch("https://api.mailbeam.dev/v1/verify", {
method: "POST",
headers: { Authorization: `Bearer ${process.env.MAILBEAM_KEY}` },
body: JSON.stringify({ email }),
});
const { score } = await res.json();
if (score >= 70) return "accept";
if (score >= 40) return "soft-confirm"; // send a double opt-in
return "reject";When to use it
Nuanced signup gating
Accept high scores automatically, send borderline scores to a soft-confirm step instead of a hard block.
Lead scoring pipelines
Feed the deliverability score into your lead model so unreachable contacts don't inflate MQL counts.
List prioritization
Sort a large list by score and send to the healthiest segment first to protect sender reputation.
Reactivation cutoffs
Set a minimum score before re-emailing a dormant contact to avoid waking spam traps.
Frequently asked questions
Ready to integrate?
Free tier includes 1,000 verifications/month. No credit card required.