addgene.org website review

About 363 KiB of JavaScript is downloaded but never used on this page. Google estimates it would make the page about 1.7 s faster on a phone.

14 files block the first paint until they finish downloading. Deferring or inlining them could save about 1.9 s.

Your mobile performance score is 64 (desktop: 99). Pages that score under 90 lose visitors before the first paint.

2 images could be 265 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen.

ZenDesk costs a phone 157 ms of main-thread work and 392 KiB of downloads while your page loads. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

The page has 1,588 HTML elements. Above 1,500, rendering and every interaction get slower on phones.

5 third-party services load with your homepage (ZenDesk, Google Tag Manager and New Relic and others), adding 782 KiB and 250 ms of main-thread time.

68 KiB could be saved by minifying JavaScript.

2 long tasks block the main thread while loading, the longest for 127 ms. During a long task the page ignores taps.

About 43 KiB of CSS is downloaded but never applied on this page.

6 files are served with short cache lifetimes, so returning visitors download them again (38 KiB).

13 KiB could be saved by minifying CSS.

Desktop scores 99 but mobile only 64. A gap that wide usually means heavy scripts and images that hit phones hardest.

Polyfills for old browsers add 10 KiB JavaScript that modern phones do not need.

Critical files load one after another instead of in parallel (3 chains). Preconnecting to key origins and preloading the hero image shortens the chain.

Real Chrome users on phones do not pass Google's Core Web Vitals on this page (28-day field data from the Chrome UX Report (opens in a new tab)). Google uses this in ranking.

Your largest element takes 11.1 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the text “Powering Scientific Sharing”.

The page becomes fully interactive after 11.3 s. Good is under 3.8 s.

Visually, the page fills in at 6.4 s (Speed Index). Good is under 3.4 s.

Real visitors wait 952 ms for your server to start answering (75th percentile). Good is under 800 ms.

The first text or image appears after 2.9 s on a phone. Good is under 1.8 s.

48 images have no width and height attributes, so the layout jumps as each one loads.

Over the last 25 four-week periods to 2026-10-10, real Chrome visitors' tap response (inp) went from 122 ms to 118 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

2 images are downloaded at several times the size a phone draws them, for example Dustin Headshot.webp at 2,133 px wide, shown at 200 px. Resized copies would save about 207 KiB.

2 images further down the page (276 KiB) download before anyone scrolls to them. Adding loading="lazy" lets the first screen load first.

By the Sustainable Web Design model, a visit to your homepage emits about 0.39 g of CO₂e: 46.3 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

2 tap targets are too small or too close together to hit reliably with a finger.

No structured data (JSON-LD), so Google can't show rich results such as your logo, ratings or FAQs.

No canonical URL, so duplicate versions of the homepage (with or without www, with tracking parameters) can split ranking signals.

Your meta description is 202 characters; Google truncates after about 160, so the end of your pitch is cut.

No XML sitemap at https://www.addgene.org/sitemap.xml, so Google discovers your pages only by following links.

1 link use generic text like “click here” or “learn more”, which tells Google nothing about the page behind it.

No twitter:card tag. X falls back to Open Graph, which is set, so this is minor.

The homepage links to 192 pages on addgene.org and 85 external pages.

There is no Organization (or LocalBusiness) JSON-LD, so search engines and AI assistants have no machine-readable facts about who runs the site: its name, logo, profiles and contact details.

There is no /llms.txt, a short Markdown guide to your key pages for AI tools (llmstxt.org). It is optional and few AI tools read it yet, so treat it as a cheap extra.

/track-order-status has no meta description, so Google writes the search snippet from whatever text it finds.

Your homepage links to 1 page by a URL that isn't its canonical one, for example /cre-lox, whose canonical is /collections/cre-lox. Linking straight to the canonical URL saves crawlers a detour and keeps ranking signals on one address.

We fetched 15 pages linked from your homepage (of 81 found) and read each the way a search engine does.

8 of 15 tappable elements near the top of the page are smaller than 24 px, hard to hit with a thumb.

6 errors were logged to the browser console while the page loaded, for example “Access to XMLHttpRequest at 'https://static.addgene.org/addgene-core/587b8fc288/public-base/sitewide.scss.post.css' fro…”.

Chrome logged issues while loading the page (“Content security policy”).

No Strict-Transport-Security header, so browsers may still try plain http first on a return visit.

No Content-Security-Policy header, the main browser-side defence against injected scripts.

X-Content-Type-Options: nosniff is missing, so browsers may guess file types.

No Referrer-Policy header, so full URLs can leak to the sites you link to.

No Permissions-Policy header to switch off camera, microphone and location for embedded content.

There is no /.well-known/security.txt telling researchers how to report a security problem to you.

On a phone, there is no call to action on the first screen: visitors have to scroll to find out what to do next.

Social proof on the homepage: 5 testimonial or review blocks. Pairing it with named testimonials or customer logos makes it far more convincing.

No phone number or email link on the homepage, so ready-to-buy visitors have one fewer way to reach you.

No guarantee or risk reducer (money-back, free trial, no credit card) is mentioned, which is often what tips a hesitant visitor.

The homepage carries about 761 words of visible text.

DMARC is set to p=none, so mail pretending to be addgene.org is still delivered. Reports are on, so moving to quarantine is the next step.

Email authentication: SPF record 25 points, plus 15 when it ends in -all (10 for ~all); DMARC record 25, plus 25 for a reject policy (15 for quarantine); a DKIM key on a common selector 10.

Before a visitor clicks anything, the page loads Google Tag Manager (measured from a US location before any click). No consent tool was detected. Visitors from the EU, UK and several US states must be asked first.

Opening the homepage sets 3 cookies (measured from a US location before any click).

No known cookie consent tool loads with the page. Some sites build their own banner, and some only show one to visitors from the EU.

Loading the homepage contacts 8 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.