“Will it change my store? Does it read customer data?”

No, and no names, emails, phone numbers or addresses. The short answers to what merchants ask before they install.

Your store

“Will it change my store or my discounts?”
No. It never edits a discount or a shipping setting: it explains, and links to the discount in your Shopify admin. There’s no storefront widget, and nothing changes for customers.
“Does it create orders or draft orders?”
No. It asks for draft order access only because Shopify’s price calculation needs it; no draft order or order is created, and nothing is charged. To see the shipping options checkout shows, it builds a cart that is never sent to checkout.
“Does it work with discount apps?”
Yes. Shopify prices the cart with every discount, apps’ included, and each applied discount shows where it comes from (a code, automatic, or the app’s name). An app’s own conditions can’t be read, so when an app’s discount doesn’t apply, the sentence says its own logic decided and to check the app’s settings.
“Does it work on Shopify Plus?”
Yes. Outside Plus, only one product discount applies per item. On Plus two product discounts can share an item when both are set up for it with matching tags, and the app reads those settings before it says one was dropped.
“What about several markets and currencies?”
A cart is priced for the country you pick, in that market’s currency. On Business a test cart can be checked in up to 10 countries. A cart in another currency whose total moved less than 1% with the exchange rate, and nothing else, is marked as moved with the exchange rate, not as a change.

“Does it read customer data?”
No names, emails, phone numbers or addresses, ever. Test carts ship to an address you type (country, region, city, postal code). On Pro and Business you can price a cart as one of your customers: the app reads only their ID, tags and order count. Refund Watch keeps, per refund, the amounts, item titles, adjustments, payment methods, the staff’s reason and the order’s customer ID.
“What does it ask access to, and why?”
Products (to pick them and check which a discount covers), discounts, draft orders (only to calculate), shipping and markets (for free shipping and shipping rates), customers (Pro and Business: pricing a cart as one of them), orders and returns (Refund Watch), and a storefront cart (the shipping options and code messages checkout shows).
“How long is my data kept?”
Price checks, store changes and refunds for 90 days. Older price checks are deleted, except each test cart’s expected and latest one and the ones its changes compare. Refund Watch reads the refunds of the last 60 days.
“What happens to my data when I uninstall?”
Shopify tells the app 48 hours after you uninstall, and everything it kept about your store is deleted then.

“How often are test carts checked?”
Once a week on Free, every day on Pro and every hour on Business. On Pro and Business also 10 minutes after a discount, shipping or market change. You can re-run any time. Compare the plans.
“What does unlimited mean?”
Up to 500 simulations a day on Pro and Business, to protect your store’s API rate limit. Saving and re-running test carts don’t count.
“Can I cancel any time?”
Yes, on Shopify’s plan page. Shopify bills the plan; a cancelled plan runs to the end of the billing cycle, then your store is on Free and keeps its test carts. Pro ($19) and Business ($49) start with a 14-day free trial.

Help shows how to use each page of the app. Why a discount didn’t apply has every reason, with the sentence the app writes for it. Anything else: support.

Install on Shopify
Add Checkout X-Ray from the Shopify App Store. It opens in your Shopify admin, on the Free plan.
Build the customer’s cart
Open the Simulator. Pick the products, type the code they used and the country it ships to, then calculate the price.
Read the answer
The price X-ray shows each layer, and every code that wasn't applied gets a sentence saying why. Save it as a test cart to have it checked again.