Shopify Plus stores hit a wall that other platforms do not. The catalog grows. The faceted navigation multiplies. International storefronts duplicate content across regions. Product variants create thousands of near-identical URLs. Somewhere around the 10,000-product mark, the site starts behaving like an enterprise property, but the Shopify architecture does not always cooperate.

The five agencies below work on that problem. Each has documented experience with ecommerce technical SEO on large stores. The list is not a ranking. It is a shortlist of partners who approach store architecture from different angles.

What Breaks First on Large Shopify Stores

A Shopify Plus store with a large catalog usually fails in the same places.

• Faceted navigation. Every filter combination generates a new URL. A store with ten filters can produce tens of thousands of crawlable paths, most of which lead to thin product grids that add no value.
• Product variant duplication. Color and size options create separate URLs or parameters. Canonicalization gets messy. Google ends up choosing which version to index, and it does not always choose the one the merchant wants.
• International storefront structure. Shopify Markets and subfolder setups create hreflang complexity. A product page in one region can be seen as duplicate content for another region if the canonical and hreflang signals do not line up.
• Collection page depth. Most Shopify collection pages are product grids with a sentence of intro copy. That thin content gets bypassed in AI Overviews, where category pages with substantive descriptive content get cited more often.

The agencies below handle these problems with different levels of specialization.

1. Organic Hackers

Organic Hackers works on Shopify Plus stores where the technical architecture has become the constraint. The best ecommerce SEO agencies for large stores tend to separate into two groups: those that understand Shopify’s Liquid templating deeply, and those that do not. Organic Hackers sits in the first group.

The work targets root causes:

• Faceted navigation generating crawlable URL patterns that should be blocked
• Product variant canonicalization sending conflicting signals
• Collection pages that need structured content depth before AI Overviews will cite them
• Product data accuracy and structured data quality
• Category page content depth for AI shopping answers

The consultancy writes ecommerce technical SEO specifications for Shopify Liquid, React/Next.js storefronts, and server configurations, then oversees implementation by internal or external developers. Custom dashboards track both traditional indexation and AI retrieval patterns.

One constraint shapes the engagement. The consultancy requires an internal development team capable of executing specifications. Strategy and developer direction stay with senior experts, which limits active client capacity. Content production sits outside the scope.

2. Greenlane Marketing

Greenlane Marketing has operated since 2005, which puts it in a different bracket from the newer technical shops. The agency’s ecommerce work spans Shopify SEO consulting, product feed optimization, and marketplace SEO.

The documented case work includes:

• A pet health brand recovering from major organic traffic losses through E-E-A-T signal strengthening
• An animal health retailer increasing Google Shopping impressions by 52% and clicks by 50% through AI-powered product description optimization at scale
• A marketplace strategy project driving an 82% ROAS increase and a 51% lift in ad-attributed sales on Sam’s Club for an incontinence product manufacturer

Greenlane’s technical scope follows the client’s CMS and technology stack. Engagements can run as one-time projects or monthly retainers, which gives enterprise teams flexibility.

3. Onely

Onely built its name on enterprise technical SEO for complex sites, and the ecommerce practice reflects that history. The agency works alongside internal development teams, delivering findings that slot into existing sprint cycles and ticket systems rather than requiring a separate workflow.

The technical scope covers:

• JavaScript SEO for client-side rendered product grids
• Server log analysis to see which URLs search bots actually crawl
• Information architecture work on category and collection page hierarchies
• Migration support for stores changing platforms or URL structures

Onely’s research on JavaScript rendering delays is cited by Google Search Central and John Mueller. The agency published a finding that Google needs 9x more time to crawl JavaScript than HTML. For stores with client-side rendered product grids, that finding has direct implications for indexation.

The engagement model is partnership rather than replacement. Onely supplements the internal SEO function with specialist depth rather than trying to own the entire program.

4. Screaming Frog

Screaming Frog built the SEO Spider and the Log File Analyser, and the agency applies the same crawling and log analysis capabilities to client work. For Shopify Plus stores with large catalogs, that infrastructure matters.

A store with 50,000 product pages and faceted navigation generates millions of crawlable URLs. Desktop tools hit limits that Screaming Frog’s in-house tooling does not.

The agency’s technical audits cover:

• Orphaned pages across large catalogs
• Broken internal links and redirect chains
• Missing or conflicting canonical tags
• Duplicate content issues at scale
• Crawl budget allocation across product and collection pages

The agency’s AI search optimisation service adds prompt tracking for high-buying-intent queries, AI bot analysis to see which pages GPTBot and ClaudeBot fetch, and sentiment analysis to understand how AI systems describe the brand.

5. Amsive

Amsive is a data-led performance marketing agency with a deep technical SEO practice. The agency won Search Engine Land’s “Agency of the Year – SEO” in 2025 and has expanded into Answer Engine Optimization with e-commerce site architecture SEO and AI discoverability work.

The AEO methodology covers:

• Technical SEO for AI discoverability through clean, fast HTML and structured data
• Brand citation consistency across platforms where AI systems pull from
• LLM share of voice analysis tracking brand citations alongside competitors
• Audience Science data tying technical prioritization to business impact

Amsive’s partnership with Profound gives enterprise clients access to AI visibility intelligence. The agency’s Audience Science approach ties technical prioritization to business impact rather than generic best practices.

Where the Technical Work Meets the Shopping Surface

AI Overviews have moved from an informational feature to a genuine shopping surface. By March 2026, AI Overviews appeared on roughly 14% of shopping queries, up from around 2% just four months earlier. The expansion has not been even.

• Purely transactional searches like “buy [product]” rarely trigger an AI Overview
• Research-and-comparison queries like “best [category] for [use case]” trigger them at much higher rates
• Category pages with substantive content get cited more often than thin product grids
• Buying guides and comparison content are overrepresented in AI Overview citations
• Product pages with detailed, structured specifications get pulled for attribute queries

The separate visibility competition is the important part. Ahrefs data from March 2026 found that citations drawn from top-10 organic results fell from 76% to 38% in about eight months. A page ranking well on Google is now a weaker guarantee of AI Overview citation than it was a year earlier. Organic click-through rates reportedly fell by around 61% specifically on queries where an AI Overview appeared.

For stores, that means the technical foundation and the content depth both matter. Structured data quality is a primary input for AI selection. Product feed completeness affects whether a store’s products get pulled into shopping answers. Category page content depth determines whether the page gets cited or bypassed.

Conclusions

Shopify Plus stores at scale face technical problems that general SEO agencies are not equipped to solve. Faceted navigation, variant duplication, international storefront structure, and collection page depth all require platform-specific expertise. The five agencies above bring different strengths to that work.

The common thread is diagnosis. A store with 50,000 URLs and crawl budget leaks needs log file analysis, not another content audit. The agencies here have documented experience finding issues that automated tools miss and translating those findings into work that development teams can execute.

Start with the diagnosis. The right agency depends on what the crawl data reveals.