Catch-All Email Verification API
Corporate domains often accept all email. Mailbeam's AI model scores catch-all addresses 0–100 so you can safely accept enterprise emails instead of blanket-rejecting them.
What Mailbeam checks
Every verification runs 7 checks in parallel and returns a structured result in under 100ms.
Catch-all domain detection
When a mail server accepts all RCPT TO commands regardless of mailbox existence, Mailbeam flags the domain as catch-all and activates the AI scoring model.
AI quality score 0–100
For catch-all addresses, a machine learning model evaluates domain reputation, MX record age, sending history patterns, and structural signals to produce a confidence score.
Explainable reason field
The `reason` field returns a machine-readable string (e.g., `catch_all_high_reputation`, `catch_all_low_confidence`) so your application can respond differently to different catch-all scenarios.
Configurable thresholds
The score is yours to interpret. Set threshold ≥ 70 for strict B2B forms, ≥ 40 for broad list acceptance. The API returns the data; your logic applies the policy.
Enterprise domain accuracy
Large enterprise domains (Fortune 500, major corporations) are catch-all but have strong reputation signals. Mailbeam scores these highly, avoiding false rejections of legitimate enterprise leads.
Combines with SMTP and MX checks
The AI catch-all score runs alongside the full verification suite. You get the MX check, SMTP result, disposable flag, and catch-all score in a single API response.
How it works
SMTP probe sent to mail server
Mailbeam probes the mail server with a RCPT TO command. If the server accepts all addresses regardless of mailbox existence, the domain is flagged as catch-all.
AI model evaluates domain signals
The AI model analyzes domain reputation from public data sources, MX record history, domain age, common corporate email patterns, and aggregate verification signals.
Confidence score generated
A 0–100 score is produced specifically for this catch-all address: 90+ = very likely monitored, 60–89 = probably active, 40–59 = uncertain, < 40 = likely inactive or trap.
Score and reason returned
The `score`, `catch_all`, and `reason` fields are included in the standard verify response. Use them to apply your own threshold logic in your application.
Integrate in minutes
import Mailbeam from "@mailbeam/sdk";
const mb = new Mailbeam({ apiKey: process.env.MAILBEAM_KEY! });
type Decision = "accept" | "review" | "reject";
function evaluate(result: Awaited<ReturnType<typeof mb.verify>>): Decision {
if (!result.valid || result.disposable) return "reject";
if (result.catch_all) {
// Apply tiered threshold for catch-all addresses
if (result.score >= 70) return "accept";
if (result.score >= 40) return "review";
return "reject";
}
// Standard address: use binary valid check + score floor
return result.score >= 30 ? "accept" : "review";
}
export async function handleLeadSubmission(email: string) {
const result = await mb.verify(email);
const decision = evaluate(result);
if (decision === "reject") {
throw new Error("Email address could not be verified.");
}
await db.leads.create({
email,
score: result.score,
catchAll: result.catch_all,
queue: decision === "review" ? "manual_review" : "active",
});
}When to use it
B2B demo request and lead capture forms
Corporate email addresses are disproportionately on catch-all domains. Blanket-rejecting catch-all addresses on B2B forms turns away real enterprise leads. Use AI scoring to accept high-confidence addresses.
Sales CRM import and enrichment
When importing B2B prospect lists, many addresses come from catch-all corporate domains. Score-based acceptance rather than binary rejection dramatically improves usable lead rates.
Cold outreach list preparation
For outbound sales sequences, use a higher score threshold (≥ 70) to include only high-confidence catch-all addresses — protecting your sending domain while maximising reachable prospects.
Enterprise SaaS product signups
Enterprise users often have corporate email on catch-all domains. A blanket catch-all rejection on your signup form turns away enterprise customers. Score-based acceptance fixes this.
Frequently asked questions
Ready to integrate?
Free tier includes 1,000 verifications/month. No credit card required.