More than a few sites that tell me they’re “on EDS” aren’t. They have a fast-looking landing page. They’ve maybe spun up a single Edge Delivery Services template somewhere on a subdomain. The marketing team waves the EDS flag in executive briefings. And then you crack open dev tools and the architecture tells a different story.
This matters because Edge Delivery is one of Adobe’s strongest performance stories. A well-built EDS implementation typically scores 90+ on mobile PageSpeed Insights (the canonical Adobe reference sites land 95+), ships content the instant an author hits save in Google Docs or SharePoint, and scales for a fraction of what a traditional CMS costs. A site that looks like EDS but doesn’t run on the EDS pipeline misses every one of those benefits. Think WordPress with a CDN in front, or a classic AEM Sites build with EDS-styled marketing pages bolted on.
Here are 7 checks that take less than a minute each. Run them on any site claiming to be EDS and you’ll know in 7 minutes whether you’re looking at the real thing or an EDS-styled lookalike.
Sign 1: There’s no aem.js in the page source
Every real EDS site loads /scripts/aem.js in the <head> (or the older /scripts/scripts.js on legacy boilerplates Adobe renamed when Helix became AEM Edge Delivery). It’s the runtime that bootstraps blocks, hydrates content, and wires up the entire framework. No aem.js or scripts.js means no EDS.
How to check: Open the site, view source (Cmd-Option-U on Mac), and search for aem.js. If you see something like:
<script src="/scripts/aem.js" type="module"></script>…you’re probably looking at the real deal. If you see wp-content, jQuery, or a 200 KB minified bundle from some agency, you’re not.
Sign 2: No data-block-name attributes anywhere in the DOM
EDS is a block-based framework. Every component on the page (hero, cards, columns, embeds) carries a data-block-name="…" attribute. That’s how the runtime knows which decorator to run, which styles to apply, and which interactive behaviors to bind.
How to check: Open dev tools, switch to Elements, and search for data-block-name. Real EDS sites have these everywhere. If the only data-* attributes you see are data-toggle or data-gtm-tracker, you’re looking at a Bootstrap/WordPress page in EDS makeup.
The block system is what makes EDS authoring fast. Authors literally write a Google Doc, Adobe parses the structure, and the runtime turns each section into a block. No blocks, no authoring loop, no EDS.
Sign 3: The hostname doesn’t resolve to *.aem.live or *.hlx.live
EDS sites serve from Adobe’s edge. Production traffic runs on main--site--org.aem.live (or the older hlx.live); preview environments live on aem.page / hlx.page. Custom domains alias to one of these via CNAME. If your DNS lookup doesn’t ultimately point at Adobe’s infrastructure, you’re not on EDS. You’re on someone else’s server.
How to check: Run dig +short www.thesite.com in your terminal and follow the CNAME chain. Or just open dev tools, hit the Network tab, and look at the response headers on the HTML request. Real EDS responses often include x-byo-cdn-type (BYO CDN setups) or Fastly-origin headers like x-served-by. These aren’t 100% definitive on their own (Fastly fronts plenty of non-Adobe sites too), but combined with the other signs they’re a strong tell. If you see Cloudflare, Vercel, or AWS CloudFront with no Adobe footprint at all, it’s a different stack.
Sign 4: /query-index.json returns a 404
This is the high-signal check. Most production EDS sites publish a /query-index.json generated from the authoring source. It’s how navigation builds itself, how internal search works, how dynamic listings pull data, and how the entire content graph stays consistent without anyone writing a CMS query.
How to check: Hit https://www.thesite.com/query-index.json in your browser. If you get a JSON response with a data array of page entries, you’re almost certainly looking at real EDS. A 404 isn’t proof of fake EDS on its own (some small sites skip the query index), but combined with the other signs it’s diagnostic. A generic site homepage at that URL means the site has no EDS content pipeline behind it at all.
Skip the manual checks. Run all 7 in one scan.
We built a free tool that runs every check in this post (and a bunch more) against any URL in 60 seconds. You get a 0-100 score, an A–F grade, and a punch list of what’s actually broken.
Run EDS Score →Sign 5: The sitemap is WordPress-shaped, not EDS-shaped
EDS auto-generates /sitemap.xml from the query index. The output is clean: one <url> entry per page, no <changefreq> or <priority> bloat, often with <lastmod> timestamps that match the authoring system.
WordPress sitemaps look completely different. They include image sitemaps, news sitemaps, Yoast-specific extensions, separate URLs for category archives and tag pages, and usually a sitemap_index.xml that references half a dozen sub-sitemaps. If the sitemap is sprawling and self-referencing, you’re on a CMS, not EDS.
How to check: curl https://www.thesite.com/sitemap.xml and eyeball the structure. EDS sitemaps are short and boring. WordPress sitemaps are long and chaotic.
Sign 6: Content is authored in a CMS admin, not Google Docs or SharePoint
This is the architectural commitment that separates EDS from every other Adobe property. Authors work in Google Docs, Microsoft SharePoint, or Adobe’s Universal Editor (the WYSIWYG Adobe shipped in 2024 specifically for EDS content). Adobe’s admin service parses those sources into structured content, and that becomes the published page. There is no WordPress-style page editor generating templated HTML, no CMS database storing page records, no revision tables to query.
If the site has a /admin URL, a wp-admin route, or a content team that logs into a CMS-style admin panel (with page records, custom post types, and database-backed revisions), that’s not the EDS authoring loop. It might still be AEM (AEM Sites and AEM Cloud Service are first-class Adobe products), but it’s not Edge Delivery.
How to check: Ask the marketing team where they edit content. If the answer is “a Google Doc,” “a SharePoint file,” or “Universal Editor,” it’s real EDS. If the answer is “we log into a WordPress/Drupal admin” or a custom CMS dashboard, it’s a different stack.
Sign 7: The mobile PageSpeed score is below 70
This is the consequence test, and it’s the one that exposes the most pretenders. Real EDS sites are designed around Core Web Vitals from the first byte of the HTML response. The block system. The lazy-decoration pattern. The auto-deferred CSS. All of it exists to put the LCP element on screen as fast as possible.
A well-built EDS site typically scores 90+ on Lighthouse mobile performance; the canonical Adobe reference sites land 95+. A “we’re on EDS” site that consistently scores in the 50s or 60s across templates is, almost without exception, not actually running the bulk of its traffic through the EDS pipeline. They’ve usually got one EDS-built landing page somewhere and the rest of the site on the old stack.
How to check: Run PageSpeed Insights on the URL. Or use our free EDS Score tool, which combines this check with the previous six.
What to do about it
If you’ve been told you’re on EDS and the 7 checks say you’re not, you have two options. One: keep the marketing copy where it is and quietly accept that you’re running a different stack. Two: actually migrate to EDS. It’s doable, but it’s a real architectural commitment, not a re-skin.
If you’re considering option two, the work splits into three buckets: setting up the GitHub repo + Adobe admin connection, building out the blocks your content needs, and migrating your existing pages into the Google Docs / SharePoint authoring source. None of it is hard in isolation, but all of it is easy to do badly. A half-built EDS implementation will score worse than the WordPress site it replaced.
This is what we do at Focus GTS. If you want eyes on your current setup, whether to confirm you’re really on EDS or to plan a migration that actually delivers the 95+ scores, reach out. The Navigator subscription ships an Adobe EDS expert into your team within a week, no SOWs, no procurement gauntlet.
Or just run the free EDS Score scan and see where your site actually lands.