How to Speed Up Shopify Pages Built With GemPages, PageFly, or Replo

Shopify pages built with a page builder like GemPages, PageFly, or Replo carry a rendering-layer cost that image optimization alone cannot remove. The page builder injects its own JavaScript framework, CSS bundle, and DOM wrappers on every page it manages, so even a text-heavy landing page with five compressed images can sit at 4 to 5 seconds on mobile. The fix is to limit the builder's scope to pages that genuinely need it and to restore native Shopify sections everywhere else.

On a recent r/shopify thread about page builder slowness, a merchant compared the same content rendered two ways: a GemPages listicle landing page measured 5 seconds on mobile, while their theme-rendered product page loaded at 3.3 seconds with comparable image weight. After the merchant swapped GemPages's header and footer for the theme's native versions, the listicle's speed index dropped to between 2 and 2.5 seconds. Most metrics improved 50 to 60 percent. The image file sizes never changed.

Why page builder pages stay slow after image optimization

The bottleneck on a page builder page is rarely image weight. It is the page builder's own rendering layer. GemPages, PageFly, and Replo each inject a JavaScript framework that re-renders content at runtime, plus a CSS bundle and a layer of wrapper elements around every section the builder controls. That overhead loads on every managed page, regardless of how light the actual content is.

A March 2026 analysis of more than 10,000 live Shopify stores quantified the cost. Stores using a page builder averaged a mobile PageSpeed score in the high 40s. Stores without one averaged in the mid 50s. PageFly specifically correlated with about a 6-point drop in mobile score across that dataset. For comparison, every regular app install in the same dataset correlated with roughly a half-point drop. That puts one page builder install at roughly the same speed cost as a dozen ordinary apps.

The LCP on these pages, tied to the largest image on the page, is the one metric that does not follow when you swap the page builder's header and footer for the theme's native versions. LCP depends on the file the browser fetches and how soon the fetch starts, not the wrapper it sits inside. Fixing it is a separate path covered in the hero image LCP guide.

If you have already compressed every image to WebP, removed unused apps, and the score has not moved, this is what you are running into. Guides on how to speed up Shopify usually start with images and apps because that is the right starting point for a typical store. They are the wrong fix for a store whose landing pages are owned by a builder.

Finding which pages your page builder manages

Open the page builder app from your Shopify admin and list every page it manages. GemPages, PageFly, and Replo each maintain their own page list inside the app interface. The pages on that list are the ones loading the builder's full bundle on every visit.

Then run a controlled comparison:

1. Pick one page that the page builder manages. Run pagespeed.web.dev on the mobile column. Record the score and the LCP.
2. Pick a comparable page on the same store that is rendered natively by your theme. A standard product page or your theme's home page works. Record the same numbers.
3. Compare. A 5-point or larger gap on mobile, with the page builder page being the slower one, is consistent with rendering-layer overhead. A 10-point gap is normal for stores running PageFly.

This isolation matters because it tells you whether your speed problem is the builder or something else. If both pages score similarly low, you have a different issue: a heavy theme, a render-blocking app, or a hosting region mismatch with your audience. Anyone working out how to speed up Shopify in those cases should start with the existing render-blocking app script audit before touching the page builder.

If the gap is wide, the next sections are for you.

How do I speed up GemPages, PageFly, and Replo pages without removing them?

Most merchants who use a page builder are not willing to give up the design flexibility it provides. Going native on every page would mean rebuilding every landing page from theme sections, which is hours of work and may not be possible at all in a theme that does not support the layouts they need.

The partial fix with the cleanest evidence in public threads is to limit the builder's scope page by page. Restore native Shopify sections wherever you do not need a custom design.

1. In the page builder, open one slow page. Switch the header and footer from the builder's versions to your theme's native header and footer. Save and republish.
2. Wait 30 minutes for the CDN cache to clear.
3. Run pagespeed.web.dev on that page. Compare to your earlier baseline.
4. If the score moved more than 5 points, repeat the swap on every other page builder page.
5. Audit the rest of the page. Any element you can replace with a Shopify native section without breaking the design (a product feature row, a testimonial block, a newsletter signup) is worth swapping.

The merchant who originally documented this on r/shopify saw the speed index drop from 5 seconds to 2 to 2.5 seconds on a single listicle page from the header and footer swap alone. The page builder still rendered the body content. Only the surrounding chrome went native. Most other Core Web Vitals metrics improved 50 to 60 percent in the same test.

Inside the page builder itself, a few settings tend to have a measurable effect:

Setting	What it does	Typical impact
Native header and footer override	Replaces the builder's header and footer with your theme's	50 to 60 percent improvement on most Core Web Vitals in one tested case
Lazy loading on builder-managed images	Defers off-screen images until scroll	200 to 400ms on LCP for image-heavy pages
Reduce nested container depth	PageFly Gen 2 Editor flag, simplifies the DOM tree	Lower Total Blocking Time, smaller page weight
Disable auto-injected fonts	Some builders inject their own webfonts on top of your theme's	100 to 300ms on First Contentful Paint

These reduce the builder's overhead. They do not remove it. Public threads do not document a page builder page reaching a mobile score above 70 through optimization alone, even after a paid Fiverr engagement. One merchant who hired a freelancer went from 7 seconds to 4 seconds on a GemPages product page and reported that GemPages overrode several of the freelancer's manual changes. If your score is still poor after the builder's own settings are tuned, you are at the floor.

What if I want to migrate off my page builder entirely?

Migrating away makes sense in three cases: when the builder is on more pages than it should be, when speed is hurting your conversion rate, or when you are inheriting a store with multiple builders layered on top of each other. The cost is the time it takes to rebuild pages in native theme sections.

Plan the migration page by page:

1. List every page the builder manages. Mark which ones could be rebuilt as native theme sections without losing design intent. Standard product pages and most policy pages usually can. Heavy long-form advertorial landing pages often cannot.
2. Duplicate your theme. Online Store > Themes > Actions > Duplicate. Work on the copy.
3. For each migrate-able page, build the equivalent in native sections on the duplicated theme. Preview side by side with the original.
4. Once a page is rebuilt and verified, change its template assignment in your live theme so the page renders from native sections instead of the builder.
5. After all migrate-able pages are switched over, uninstall the page builder from Apps. Then clean the residual code.

Step 5 is the part most stores skip. Uninstalling a page builder does not remove the JavaScript and CSS the builder injected into your theme. The leftover code keeps loading on every page, including the ones you just rebuilt natively, until you remove it manually.

To remove the residue:

1. Open Online Store > Themes > Edit code on your duplicated theme.
2. Search theme.liquid for the builder's name (gempages, pagefly, replo). Delete any matching <script> tags or {% include %} lines.
3. Open every file under Templates, Sections, Snippets, and Layout. Search each for the builder's name. Delete what you find.
4. Open the Assets folder. Look for .js, .css, or .liquid files named after the builder. Delete them.
5. Check Config > settings_data.json for orphaned config blocks. Remove them.

If your store has had multiple page builders over its lifetime, the search-by-name step gets complicated fast. One developer who specializes in store takeovers warned that "trails of multiple page builders littered through the codebase" are nearly impossible to clean up without deep theme work. When merchants ask how to speed up Shopify after they already migrated off a builder and the residue is still loading, this manual cleanup is the answer. If you suspect this is your store, a help1 expert can do the residual code audit with you. Your first 15 minutes are free.

How does the speed cost compare across page builders?

Public data on individual page builders is uneven. PageFly has the cleanest single number from the large-store dataset. GemPages and Replo show up in case studies but not in clean correlations across stores. Here is what is documented:

Page builder	Documented mobile score impact	Source quality
PageFly (across 10,000+ stores)	about a 6-point drop correlation	Strong: large dataset, public methodology
PageFly (single landing page)	27 to 28 mobile vs 90+ desktop	Single-store thread, no comparison page
GemPages (after Fiverr optimization)	7 seconds to 4 seconds, still poor	Single-store thread, optimizer noted GemPages overrode some changes
GemPages (header swap fix)	5 seconds to 2 to 2.5 seconds	Single-store experiment, before and after on the same page
Replo	"Pages are heavy"; merchants seek ways to convert to Liquid	Multiple thread mentions, no quantified score data
No page builder (any theme)	mid-50s average mobile score	Strong: 10,000+ store dataset

The pattern is consistent across all three builders even where the data is anecdotal: a page builder page is slower than a comparable native theme page on the same store. The size of the gap depends on the builder, the number of nested containers in the page, and how aggressively the merchant has tuned the builder's own settings.

For a solo merchant figuring out how to speed up Shopify on a tight budget, the practical implication is that not every page needs the builder. Use it where the design flexibility wins you something measurable, like a heavily branded campaign landing page or an advertorial that converts well. Use native sections everywhere else. That single split usually closes most of the gap without a full migration.

The help1 store scanner flags which of your pages load a page builder bundle and shows the speed delta against your native theme pages on the same store, so you can decide migration on actual data instead of guessing.

Open your page builder app right now and pick one slow page. Switch its header and footer from the builder's versions to your theme's native header and footer, save, wait 30 minutes for cache, and run pagespeed.web.dev on the mobile column before and after. If the score moves by 5 points or more, you have your fix and you can roll it out to every other builder page in an evening. If it does not move and you suspect older builder residue is still loading on top of the active builder, a help1 expert can audit your theme code for leftover script tags in a single 15-minute session.