How OfferGuard stops abuse before it costs you
From installation to real-time blocking in under 2 minutes. Here is exactly what happens at every step. The 5-signal detection chain is the centerpiece.
Install from the Shopify App Store
Click "Install" and authorize OfferGuard. The app automatically configures its checkout extension — no theme editing, no code changes, no developer needed.
OfferGuard uses Shopify's official Checkout Extensions API. It runs natively within the Shopify checkout. No script injection, no redirects, no theme file modifications.
Create your first protection rule
Select the product, collection, or discount code you want to protect. Choose which detection signals to enable and set your matching thresholds.
Start with the Watchdog plan to see how many repeat buyers your promotions attract using email detection alone. Then upgrade to Sentinel to enable all 5 signals for comprehensive protection.
OfferGuard activates at checkout
When a customer adds a protected product to their cart and enters checkout, OfferGuard begins its detection process automatically. No customer action required.
The checkout extension monitors cart contents. If a protected product or active discount code is present, the detection engine engages transparently.
All 5 signals checked in parallel
As the customer fills in their checkout details, OfferGuard captures and normalizes their email, phone, address, IP, and device fingerprint. All five signals are checked against your order history simultaneously.
The entire check completes in under 50 milliseconds. The customer experiences zero delay. Email is normalized (Gmail dots removed, plus aliases stripped, disposable domains blocked). Phone numbers are format-standardized. Addresses are fuzzy-matched. IP subnets are compared. Device fingerprints are identified.
Instant decision
If the number of matching signals exceeds your configured threshold, the checkout is blocked with a clear, non-accusatory message. If the customer is genuinely new, checkout proceeds normally.
The default message reads: "This offer is available to first-time customers only. You can still complete your purchase at the regular price." Customers are never accused of fraud. The message is customizable.
Post-purchase processing
For orders that complete, OfferGuard processes the results: tagging orders and customers, assessing risk, and optionally holding fulfillment for orders that show some risk signals.
Every detection decision is logged with full detail. You can review the complete detection chain for any order from your Shopify admin — which signals matched, confidence scores, and the matched previous order.
Detection in action
Real-world scenarios showing how each signal catches a different type of abuse. A repeat buyer would need to defeat all five simultaneously.
Gmail Alias Attempt
BlockedEmail normalization strips dots and plus alias. Both resolve to [email protected].
Different Email, Same Phone
BlockedEmail is genuinely different. But phone numbers normalize to the same number.
Address Variation
BlockedStreet abbreviation normalized. Unit designation standardized. 96% similarity.
Incognito + Disposable Email
BlockedDisposable email blocked immediately. Device fingerprint matches despite incognito.
The 5-signal detection chain
Every checkout runs through all active signals in parallel. The results are combined to make a single, confident decision in under 50ms.
Ready to see it in action?
Install OfferGuard in under 2 minutes. The Watchdog plan is free forever.
Install Free on Shopify