Bundle block now ships half the JavaScript

The bundle block runs a script on your product page to switch tiers, re-price the cards, and add the right quantity to the cart. That script has been growing for months as we fixed things, and it had become the heaviest file we ship.

It is now half the size: 15.4 KB down to 7.9 KB compressed, a 49% cut. It also comes in under Shopify's recommended ceiling for an app block script for the first time.

What this changes for you

Nothing to click, and nothing to redo. Your bundles look and behave exactly as they did. Your settings, tiers, gifts and design presets are all untouched. The only difference is that product pages carrying a bundle block download less code before the block becomes interactive.

Being straight about the scope: this is one file getting smaller. It helps pages with a bundle block on them, it will not change your store's speed score on its own, and your own images and theme are still the bigger factors on most stores.

How we did it

The script carries a lot of written explanation inside it, notes for whoever touches that code next, and it turned out those notes were 43% of what shoppers were downloading. We had assumed they cost almost nothing, so we had never looked. They did cost something.

The notes now stay in our source and shoppers get a compressed version, so we keep the documentation and your customers stop paying for it. We also added a check that fails our build if this file ever creeps back over Shopify's recommended size, so it cannot quietly grow again.

If you spot anything off with your bundles after this, the chat at the bottom right reaches us.