How to stop free trial abuse in SaaS

Free trials create a predictable abuse target: one account gets value, the account is discarded, and the attacker starts again with a new email, IP, device, or payment method.

The mistake is treating trial abuse as a billing problem only. In most SaaS products, the risk signals appear before billing: disposable inboxes, repeated devices, hosting-network traffic, suspicious domains, and behavior that jumps straight to expensive features.

Protect value, not only the signup form

The best trial-abuse control is graduated access. Let low-risk users start smoothly, challenge uncertain users, and delay high-value actions until the account earns trust.

Examples of value gates include API-key creation, exports, team invites, bulk actions, credits, webhooks, and paid-feature trials.

Score the trial start

const assessment = await requestGuard.assess({
  ip,
  email,
  domain,
  userAgent,
  event: "trial_start",
  userId,
  sessionId,
  metadata: {
    plan: "trial",
    invited_by: invitedBy,
    requested_credits: requestedCredits,
  },
});

if (assessment.decision === "block") {
  throw new Error("Trial unavailable");
}

if (assessment.decision === "challenge") {
  // Require email verification, CAPTCHA, or an OAuth login.
}

Use the decision to decide whether the user receives immediate value, limited access, verification, review, or a block.

Signals to combine

• Disposable or risky email domains.
• Free-provider emails for high-value B2B trials.
• VPN, proxy, Tor, datacenter, and suspicious ASN traffic.
• Repeated device or session patterns.
• Domain mismatch between claimed company and email.
• Fast path to expensive features.

No single signal proves abuse. The decision gets stronger when multiple signals agree.

Practical policy

Low-risk users should convert with little friction. Medium-risk users should verify before accessing expensive features. High-risk users should be blocked or sandboxed.

RequestGuard helps you make that policy enforceable in your backend: score the event, store the request ID, and apply the same decision model everywhere trial value can be abused.