After a Vue 3 migration, an autocomplete with 700 domain zones took about 12 seconds to open. The cause was an old quadratic deduplication that became expensive once it read every object through a reactive Proxy.
A cleaner visual editor moved widget controls into the storefront preview. When custom code breaks that preview, the controls disappear with it. This is how I found that gap and the recovery mode I built for it.
Invisible CAPTCHA looks like a script tag. Across several generations of store forms it turned into async-state bugs and a production rollback caused by a settings record that didn't exist.
How a custom tokenizer for HTML with Liquid, JavaScript and CSS islands made suggestions follow the cursor, and why the editor shipped as a versioned package with a three-function browser API.
A storefront library cached product data for a fixed time, so pages either showed stale data or re-requested products that hadn't changed. Comparing each product's update timestamp cut product-data requests by about 70%.