How to Fix a Slow Shopify Store — Full Checklist (2025)

If your Shopify store feels sluggish, loads in more than a few seconds, or fails Core Web Vitals, you're not alone. Most merchants eventually search for how to fix a slow Shopify store after they start adding apps, custom code, and large images. This article gives you a straightforward checklist you can follow "€” whether you're a store owner, marketer, or developer "€” to restore your store"€™s speed step by step.

1. Quick checks to confirm your Shopify store is slow

Before touching any code, you need to confirm there"€™s really a performance problem. These quick checks take less than 10 minutes and give you an honest baseline.

• Open your store on 4G: Use your phone on a mobile network. If your homepage or product pages feel slow, your customers feel it too.
• Run a PageSpeed Insights test: Test your homepage, a product page, and a collection page. Note the mobile scores and the Core Web Vitals section.
• Check for obvious bloat: Pop-ups, chat widgets, review apps, and tracking scripts are often the first suspects when Shopify site speed optimization becomes necessary.
• Ask your team: If your support team or marketing team says "€œthe site feels slow"€, treat that as a signal to start the checklist.

2. Common reasons Shopify stores become slow

Once you know the store is slow, the next step is understanding why. After hundreds of audits, we see the same causes of poor performance over and over again.

3. Pre-optimization audit checklist

Before you start making changes, capture a snapshot of how your store performs today. That way you can see what your work actually changed.

4. Real Before & After checklist example

One FASTRANK client, a Shopify Plus store selling premium outdoor gear, came to us with a slow mobile experience and weak Core Web Vitals. Their store had a lot of apps, large hero images, and a customized theme that hadn"€™t been cleaned up in years.

After going through a structured fix slow Shopify store checklist "€” removing unused apps, compressing images, deferring scripts, and stabilizing layout shifts "€” their mobile PageSpeed score jumped from 38 to 92, LCP dropped from 6.2s to 1.8s, and mobile conversions increased by 22%.

5. Full checklist to fix a slow Shopify store

Here"€™s the exact checklist we use internally when we deliver a shopify speed optimization service. You can go through it yourself or use it as a framework when working with a developer.

3.1 Removing or Replacing Performance-Killing Shopify Apps

Third-party apps are the number one reason why otherwise healthy Shopify stores become slow. Each installed app injects JavaScript, CSS, and external requests "€” often on every page. This additional code increases main-thread work, blocks rendering, and negatively impacts Core Web Vitals such as LCP and INP.

This step focuses on structured cleanup and smart removal to restore performance safely.

The App Cleanup Checklist

1) Surgical App Uninstall

Action: Remove any app not actively used in the last 30 days. Unused apps continue loading scripts, slowing the store globally.

Tip: If an app is needed only for a specific page, configure it to load scripts on that page only, not site-wide. For more insights, see our article:
Best Shopify Apps That Slow Down Your Store (2025 Analysis)

2) Code Scavenging (Critical Step)

Deleting an app does not remove its leftover code. Many apps leave behind JavaScript files, CSS, theme snippets, and script tags inside theme.liquid.

Action: Manually audit your theme and asset files to remove residual code.

Expert Insight: Use Chrome DevTools "†’ Coverage Tab to identify unused JS/CSS added by deleted apps.
Related guide:
Shopify Core Web Vitals: Why Your Store Is Slowing Down & How to Fix It

3) App Consolidation

Action: Replace multiple single-purpose apps (popups, reviews, badges) with one lightweight multipurpose tool. This reduces external script requests and improves speed immediately.

See real examples:
Before/After Shopify Speed Optimization "€“ Case Study

4) Prefer Native Shopify Features

Action: Use built-in Shopify theme features (filters, FAQ accordion, tabs, announcement bar) instead of third-party apps whenever possible.

More best practices inside:
Shopify Speed Optimization Guide (2025)

Step 2: Fix image bloat

Image optimization is one of the fastest ways to see improvement:

• Keep hero and product images under ~200KB when possible.
• Use WebP versions instead of only JPG/PNG.
• Enable lazy loading for images below the fold.
• Set width/height attributes to avoid CLS.

Step 3: Reduce render-blocking CSS and JS

Once images and apps are under control, move to critical resources:

• Inline only the CSS needed for above-the-fold content.
• Load the rest of your styles asynchronously or with appropriate media attributes.
• Use defer for non-critical JavaScript that doesn"€™t affect the first paint.
• Group small scripts together instead of loading dozens of tiny files.

Step 4: Stabilize Core Web Vitals

A proper shopify core web vitals fix focuses on LCP, CLS, and INP:

• Ensure the LCP element (usually the main hero image or heading) loads quickly by prioritizing it in the HTML and limiting competing requests.
• Reserve space for images, banners, and embeds so they don"€™t push content down while loading.
• Limit heavy scripts that keep the main thread busy and hurt INP.

Step 5: Use a CDN and compression

Shopify already uses a global infrastructure, but you can often squeeze out more performance by:

• Using a CDN like Cloudflare in front of your store for better caching and routing.
• Ensuring Brotli or GZIP compression is enabled for text-based resources.
• Caching HTML pages for anonymous visitors on landing pages where it"€™s safe.

Step 6: Re-test and document improvements

After working through the checklist, repeat the same tests you ran at the beginning. Capture new PageSpeed Insights screenshots and GTmetrix waterfalls. This gives you a clear before/after story to share with your team or with a potential client.

6. Business impact of completing the checklist

The goal of this checklist isn"€™t just a nicer score in a lab report. When you systematically improve your store"€™s speed, you usually see:

• Higher conversion rate: Shoppers stop dropping off before product pages finish loading.
• Lower bounce rate: Visitors stay on the site longer and view more pages per session.
• Better ad efficiency: Faster landing pages improve Quality Score, which can reduce CPC on Google and Meta.
• Stronger SEO: A faster, more stable experience supports your long-term organic rankings.

7. DIY fixes vs hiring a Shopify speed expert

Many checklist items "€” like app cleanup and basic image compression "€” are safe to handle yourself. But other tasks, especially those that touch theme files and Liquid templates, can break layouts or checkout if done incorrectly.

If your store is a key revenue channel, or you"€™re running paid ads to slow pages, consider working with a specialist. A good partner offering improve shopify speed service will:

• Run a detailed audit and explain findings in plain language.
• Follow a safe deployment process with backups.
• Focus on measurable metrics (Core Web Vitals, load time, conversions).
• Provide a clear before/after report.

At FASTRANK, we provide a structured shopify performance optimization process and dedicated plans for store owners who want expert help instead of spending weeks debugging code themselves. You can view our Shopify optimization plans if you’d rather hire a Shopify speed expert than go through every step alone.

8. Frequently asked questions

Here are some of the most common questions we hear from merchants going through this checklist for the first time.

9. How to get started with Shopify performance optimization

If this feels like a lot, remember you don"€™t need to tackle every point in one day. Start with the easiest wins: apps, images, and obvious layout issues. Then work your way toward deeper technical changes.

• Use this article as your working checklist and tick off items as you go.
• Keep screenshots of your results so you can see how much faster your store becomes.
• Share the checklist with your developer or agency so everyone is aligned.

And if you'd rather have an expert handle everything, our team at FASTRANK offers a structured shopify site speed optimization service with clear pricing, guaranteed improvements, and a detailed before/after report.