--- title: "Store Speed and Code Guides for Shopify and WooCommerce" description: "Pass Core Web Vitals and fix what slows your store: the apps behind a slow Shopify store, WooCommerce server tuning and safe theme code edits." url: "https://carthacker.com/category/customization/" image: "https://carthacker.com/wp-content/themes/carthacker-core/assets/og/customization.jpg?v=1791719545" publisher: "CartHacker (carthacker.com)" language: "en" --- Engineering # Code & Customization Copy-paste snippets, theme surgery and performance tuning for owners who are not afraid of the code editor - every line is production-tested. ## [How to Edit Your Shopify Theme Code Without Breaking Your Store](https://carthacker.com/customization/edit-shopify-theme-code/) September 17, 2026, by [Adrian Wadowski](https://carthacker.com/author/adrian/) [![The Shopify code editor with the theme.liquid file of a live theme open: the file list on the left with the assets, layout and locales folders, and the head section of theme.liquid with meta tags, the canonical link and the title template](https://carthacker.com/wp-content/uploads/edit-shopify-theme-code-cover.jpg)](https://carthacker.com/customization/edit-shopify-theme-code/) Most changes to a Shopify store need no code at all, and the ones that do go into a copy of your theme first. Where each kind of change belongs, how to find theme.liquid and paste a snippet in the right place, what Custom CSS can do, what a theme update does to your edits, and how to undo a mistake. [Code & Customization](https://carthacker.com/category/customization/) ## [Why Your WooCommerce Store Is Slow, Starting With the Server](https://carthacker.com/customization/woocommerce-slow/) August 27, 2026, by [Adrian Wadowski](https://carthacker.com/author/adrian/) [![Bar chart of the server time for one WooCommerce product page on one CPU core: no OPcache 473 ms, OPcache on 100 ms, Redis with the Predis client 105 ms, Redis with the PhpRedis client 103 ms, Cache Enabler page cache 1.7 ms, nginx server page cache 1.1 ms](https://carthacker.com/wp-content/uploads/woocommerce-server-time-by-setup.png)](https://carthacker.com/customization/woocommerce-slow/) A 600-product WooCommerce store measured through every layer a host controls, from OPcache and page caching to Redis, PHP workers, plugins and cart fragments, with the fixes in the order they pay off. [Code & Customization](https://carthacker.com/category/customization/) ## [How to Find What Is Slowing Down Your Shopify Store](https://carthacker.com/customization/speed-up-shopify-store/) August 13, 2026, by [Adrian Wadowski](https://carthacker.com/author/adrian/) [![Bar chart of sites passing all three Core Web Vitals on mobile in August 2026, by Shopify app installed: Instafeed 82.7%, Smile App 81.3%, Privy App 80.8%, all Shopify stores 76.5%, Judge.me 75.5%, Loox 75.1%, PageFly 74.7%, Klaviyo 71.1%, Okendo 71.0%, Vitals 70.3%, Yotpo Reviews 66.5%, Booster Page Speed Optimizer 63.5%, Intelligems 56.5%](https://carthacker.com/wp-content/uploads/shopify-apps-core-web-vitals.png)](https://carthacker.com/customization/speed-up-shopify-store/) A step-by-step method to find the apps, theme code, photos and videos that slow a Shopify store down, tested on a real store, with the fixes and size limits that work. [Code & Customization](https://carthacker.com/category/customization/) ## [What Google's Speed Scores Mean for Your Store](https://carthacker.com/customization/core-web-vitals/) August 6, 2026, by [Adrian Wadowski](https://carthacker.com/author/adrian/) [![Core Web Vitals Monitoring for camelway.eu over seven days of real visits: Loading 1.5 s, Responsiveness 98 ms and Stability 0.007, all three rated good](https://carthacker.com/wp-content/uploads/core-web-vitals-hero-1.jpg)](https://carthacker.com/customization/core-web-vitals/) The three numbers Google grades your store on, where they come from, why small stores see no data, and which fix moves each one on Shopify and WooCommerce. [Code & Customization](https://carthacker.com/category/customization/) --- Source: [Store Speed and Code Guides for Shopify and WooCommerce](https://carthacker.com/category/customization/), CartHacker. ## Free tools from CartHacker - [Store Speed Test](https://carthacker.com/store-speed-test/): Check your store's Core Web Vitals for free. - [Core Web Vitals Monitoring](https://carthacker.com/core-web-vitals-monitoring/): Monitor your store's Core Web Vitals every day, for free. - [Trust Seals & Badges](https://carthacker.com/trust-badges/): Add trust badges under your Add to cart button. - [QR Code Generator](https://carthacker.com/qr-code-generator/): Make a QR code you can still change after printing. - [PDF Tools](https://carthacker.com/pdf-tools/): 39 free PDF tools that run in your browser: merge, split, convert to and from Word, Excel and JPG, sign, redact and protect. No file is ever uploaded. - [CartHacker Premium](https://carthacker.com/premium/): one subscription, monthly or yearly, that upgrades every tool at once: - 50 trust badges in 30 languages, switched automatically - 180 days of Core Web Vitals, per page - All 39 PDF tools, unlimited and never uploaded - 200 QR codes, tracked and editable after printing - No ads on any guide or tool - Every new guide 2 weeks before the public - Product Feed Manager and new tools included - Every quota and price, tool by tool: https://carthacker.com/llms.txt