Shopify App Conflicts: Why One Install Can Break Checkout

Every storefront app adds its own JavaScript to your pages, and there's no sandbox isolating one app from another or from your theme. When two pieces of code touch the same thing — the cart, a global variable, the DOM around the buy button — they can conflict: one throws an error, halts, or overrides the other, and a storefront function stops working.

App conflicts rarely produce an error page. The store returns HTTP 200, the admin looks normal, and the only symptom is a function that quietly fails — Add to Cart that doesn't fire, a cart that won't advance, a pixel that stops firing. A merchant checking their own site on desktop often sees nothing wrong. See why an HTTP 200 store can still be broken.

You approve an app once, but it updates itself continuously. An update can change a script, duplicate a snippet, or introduce an error at any time — with no changelog you see and no prompt. That's why "we didn't change anything and checkout broke" is so common: you didn't, but an app did.

Two layers help. App-conflict monitoring fingerprints every app and flags when one changes or starts erroring. Checkout monitoring proves whether customers can still buy. Together they tell you both that a customer can't check out and which app update lines up with the break.