Coupon and referral abuse: stop self-referral and code farming

The threat

A first-order discount or a referral reward is a payout. Whoever can create an account cheaply can collect it repeatedly, and shared codes spread beyond the audience you meant.

What we stop

• One-time coupons claimed again from the same device, email or household.
• An invitee who is, in practice, the inviter on another account: same device, same browser profile or same computer and network.
• Scripted coupon and referral claims.

Two checks, two calls

For coupons, ask for an eligibility decision with a coupon claim kind. For referrals, bind the inviter’s devices when they log in, then compare the invitee’s device when they claim. The relation answer is advisory: it returns graded signals and a suggestion of allow, review or deny, and you decide.

Your project handles the trial kind out of the box. Further claim kinds, such as a coupon or a sign-up bonus, and named quotas are switched on for your project on request.

Compare an invitee with the inviter

// At the inviter's login: remember which devices this user uses (does not spend the attestation)
await fetch('https://api.fpchecker.com/v1/subjects/bind', {
  method: 'POST',
  headers: { 'content-type': 'application/json', 'X-Secret-Key': process.env.FPCHECKER_SECRET_KEY },
  body: JSON.stringify({ subject: session.userId, attestation }),
});

// When the invitee claims: compare their device with the inviter's
const r = await (await fetch('https://api.fpchecker.com/v1/subjects/relation', {
  method: 'POST',
  headers: { 'content-type': 'application/json', 'X-Secret-Key': process.env.FPCHECKER_SECRET_KEY },
  body: JSON.stringify({ subject: inviterUserId, attestation: inviteeAttestation }),
})).json();
// r.suggestion is "allow", "review" or "deny"; it is advice, you decide

Frequently asked questions