Email Verification for Online Marketplaces
Fraud in marketplaces starts with a fake account. Verify email addresses at registration to cut off fraudulent sellers and buyers at the entry point.
How fake accounts undermine marketplace trust
A marketplace's value depends on trust between buyers and sellers. Fake or fraudulent accounts erode that trust — and the cost is not just direct fraud losses, but platform reputation.
Fraudulent sellers use disposable emails to avoid bans
A seller banned for scamming buyers returns with a new account using a throwaway email. Without email verification, platform bans are trivially bypassed.
Fake buyer accounts game review systems
Sellers with multiple fake buyer accounts inflate their own ratings. Disposable email detection stops the most common form of review manipulation.
Chargeback fraud concentrates in unverified accounts
Buyers who use throwaway emails to make purchases and then initiate fraudulent chargebacks are common in marketplaces. A verified email is a lightweight accountability signal.
Trust & Safety teams waste time on obvious fakes
When even basic email verification is absent, T&S teams spend disproportionate time on clearly fake accounts that could have been stopped at registration.
Verify at registration for both buyers and sellers
Different account types warrant different verification thresholds. Sellers transacting money warrant stricter checks than browsing buyers.
Tiered verification by account type
Apply a strict threshold (score ≥ 70) for seller accounts and a more lenient one (score ≥ 40) for buyer registrations, using the same API with different configuration.
Disposable domain blocklist
Block 50,000+ known throwaway domains. A seller who can't register with a fake email has to commit a real address — a meaningful deterrent against casual fraud.
Catch-all business domain handling
Many legitimate sellers use business email domains that are catch-all. Mailbeam's AI scoring distinguishes real business addresses from low-quality catch-all registrations.
Webhook for async post-verification
For high-volume marketplaces, verify asynchronously using webhooks and hold accounts in a pending state until verification completes.
Implementation
Copy-paste ready. Replace the API key and integrate with your existing flow.
import Mailbeam from "@mailbeam/sdk";
const mb = new Mailbeam({ apiKey: process.env.MAILBEAM_KEY! });
const THRESHOLDS = { seller: 70, buyer: 40 } as const;
export async function registerAccount(
email: string,
accountType: "seller" | "buyer"
) {
const result = await mb.verify(email);
const minScore = THRESHOLDS[accountType];
if (!result.valid || result.disposable) {
throw new RegistrationError(
"Please use a permanent, valid email address.",
result.suggestion
);
}
if (result.score < minScore) {
throw new RegistrationError(
"This email address does not meet our verification requirements."
);
}
return await db.accounts.create({ email, type: accountType });
}Real-world example
Craftloop (placeholder)
Handmade goods marketplace
Challenge
A wave of fraudulent sellers listing non-existent items used disposable emails to evade bans. 12% of new seller accounts in one quarter were later identified as fraud.
Result
After adding Mailbeam verification for seller accounts, fraudulent seller registrations dropped by 89% in the following quarter.
Fraudulent seller accounts 12% → 1.3% of new registrations
* Example based on anonymized customer data. Results may vary.
Recommended plan
Growth
Marketplaces with active acquisition typically register 10,000–100,000 accounts per month. Growth plan covers this range. The tiered threshold approach (seller vs buyer) requires only the single verify endpoint.
Frequently asked questions
Ready to get started?
Free tier includes 1,000 verifications/month. No credit card required.