mankenberg.com website review

15 files block the first paint until they finish downloading. Deferring or inlining them could save about 1.2 s.

Your mobile performance score is 84 (desktop: 85). Pages that score under 90 lose visitors before the first paint.

Web fonts hide text while they load. Setting font-display: swap shows text immediately (about 450 ms).

About 13 KiB of CSS is downloaded but never applied on this page. Google estimates it would make the page about 150 ms faster on a phone.

10 KiB could be saved by minifying JavaScript.

3 files are served with short cache lifetimes, so returning visitors download them again (131 KiB).

1 image could be 45 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen.

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

3 KiB could be saved by minifying CSS.

The layout shifts by 0.285 while loading, so content jumps under the reader's thumb. Good is under 0.1.

Over the last 25 four-week periods to 2026-10-17, real Chrome visitors' tap response (inp) went from 72 ms to 92 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

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

h2_986x800startseite-min.gif weighs 15.5 MB. On a phone connection a single image that size takes seconds.

3 images (15.6 MB) are JPEG, PNG or GIF. The same pictures as WebP or AVIF are usually much smaller at the same quality, and every current browser shows them.

2 images further down the page (15.6 MB) 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 0.29 g of CO₂e: 34.6 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

All page content should be contained by landmarks: 6 elements on the page fail this check, rated moderate by axe-core.

Landmarks should have a unique role or role/label/title (i.e. accessible name) combination: 1 element on the page fails this check, rated moderate by axe-core.

2 form fields have no label, so screen readers announce an empty box and autofill guesses.

Alternative text of images should not be repeated as text: 1 element on the page fails this check, rated minor by axe-core.

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

There are 2 <h1> headlines (“Your reliable partner in challenging times” and “Hydrogen – Energy source of the future”). One clear main headline is easier for people and search engines.

Your meta description is 161 characters; Google truncates after about 160, so the end of your pitch is cut.

No XML sitemap at https://www.mankenberg.com/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.

The homepage links to 94 pages on mankenberg.com and 21 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 https://www.mankenberg.com/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.

https://www.mankenberg.com/en/vacuum-control-valves/products has no meta description, so Google writes the search snippet from whatever text it finds.

https://www.mankenberg.com/zh has under 150 words in the HTML. Thin pages rarely rank; if the text loads with JavaScript, crawlers that don't run it see even less.

We fetched 15 pages linked from your homepage (of 78 found) and read each the way a search engine does.

7 of 21 tappable elements near the top of the page are smaller than 24 px, hard to hit with a thumb.

2 images are served at too low a resolution for sharp phone screens.

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 461 words of visible text.

Opening the homepage sets 1 cookie (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.