Your discounts look safe. They’re not.

Customers combine your promotions in ways you never intended. Promo Firewall finds every dangerous stack.

Available Soon on Shopify
Shopify App Store Read-only access First scan free
68.4%
Effective Discount
Classic Cotton Tee (M) $19.99
Merino Wool Sweater (XL) $89.00
Buy Any Tee Get Sweater Free −$89.00
Premium Collection 35% Off −$7.00
Subtotal $12.99
Shipping $7.99
Free Shipping on All Orders −$7.99
Customer pays $12.99
Exploitable Mar 1 – Apr 15
The blind spot

Each promotion makes sense alone.
Shopify lets them combine.

Your customers find stacking combinations you never intended. A code plus an automatic sale plus free shipping can quietly reach 68% off — and Shopify won't warn you.

your-store.myshopify.com/admin/apps/promo-firewall

One click. Two minutes. Full picture.

Every possible discount combination tested against your live catalog. If it stacks, we find it.

your-store.myshopify.com/admin/apps/promo-firewall
How it works

Install once.
Know everything.

01

Install

One click from the Shopify App Store. Read-only access to your discounts and products — nothing else.

02

Automatic scan

Starts the moment you install. Every feasible discount combination tested against your real products. Under two minutes.

03

Your report

Each risky stack ranked by severity, with the exact cart that triggers it. Results appear on your dashboard automatically.

What you get

Your discount risk, laid bare.

Every scan tests your real discounts against Shopify's full combinability matrix — all six types, all stacking rules.

Every combination

Not spot checks. Every feasible way your discounts can stack — codes, automatics, BXGY, free shipping — tested exhaustively against your real products.

Ranked by severity

Critical, Warning, or Safe. Your biggest margin risks surface first so you know exactly where to act.

Proof, not guesses

Each finding includes a witness cart — the exact products, quantities, and applied discounts that trigger the stack.

Why it matters

Stacking is silent until it isn’t.

Discount combinations that look safe individually can interact in ways you wouldn’t expect. One overlooked stack can erode margin on every qualifying order.

Without visibility

Two reasonable promotions. One cart that exploits both.

You run “35% off premium” alongside “Buy a tee, get a sweater free.” Each looks safe alone. A customer combines them and checks out at 68% off — you find out from the margin report.

68% effective discount, discovered after the fact
With Promo Firewall

Every risky interaction flagged before a single order ships.

The scan finds the stack, shows the exact witness cart, and scores the severity. You decide whether to adjust combinability, tighten the code, or accept the risk — on your terms.

<2 min to full visibility after install
Run promotions with confidence.

The more discounts you run, the harder it is to reason about every combination. Promo Firewall does the exhaustive check.

Pricing

Your catalog size sets your plan.

No plan picker. The app reads your variant count and assigns the right tier automatically. All billing through Shopify.

Free
Any store size
$0
3 full scans included. First runs automatically on install.
  • Full safety report
  • Severity scoring
  • Witness cart details
Pro
Unlimited scans
auto-assigned by variant count
Up to 5K variants
$29 /mo
most stores
Up to 50K variants
$79 /mo
Up to 500K variants
$149 /mo
Unlimited scans Auto re-scan on changes Full safety report Severity scoring
Available Soon on Shopify

No credit card for free scans. Pro activates based on variant count. Cancel anytime from Shopify admin.

FAQ

Common questions.

Everything you need to know before installing.

No. Promo Firewall uses read-only access. We never create, edit, or delete any of your discounts, products, or other store data. We only read your active promotions to analyze stacking risk.
Under two minutes for most stores. The scan analyzes only the discount combinations Shopify would actually allow together, so it's fast even for stores with dozens of active promotions.
Not at all. Promo Firewall runs entirely in the background using Shopify's Admin API. There's no theme code, no storefront script, no DNS change, and no proxy. Your customers will never notice it.
All of them — discount codes (percentage, fixed amount, BXGY, free shipping), automatic discounts, and free shipping thresholds. We test every possible combination against Shopify's current combinability rules.
The number of product variants determines how many discount-product interactions need to be tested. Your plan is set automatically based on your catalog size: up to 5K variants ($29/mo), up to 50K ($79/mo), or up to 500K ($149/mo). You don't choose — the app detects your variant count and sets the right tier.
Uninstall from your Shopify admin at any time — no emails, no support tickets. Billing is handled entirely through Shopify, so cancellation stops charges immediately.

Know what your promos are really costing you.

Free scan. Read-only. Under two minutes. No credit card.

Available Soon on Shopify

Free plan includes 3 full scans  ·  No credit card required