Performance Optimization
Every second of loading time costs you visitors, rankings, and ultimately revenue. We'll find the bottlenecks on your website and fix them.
Performance Optimization Agency
A slow website loses visitors before they even get to the first paragraph. Performance optimization ensures that technology and user experience work in harmony.
Loading times
that keep visitors on the site
Core Web Vitals
in the green zone
Ranking Advantages
Through Technical Excellence
Why Milliseconds Make the Difference in Conversions
Visitors decide within the first few seconds whether to stay or leave. Studies show that once the load time exceeds three seconds, the bounce rate increases dramatically. This affects not only the user experience but also your conversion rate directly. Google considers page speed a ranking factor, especially on mobile devices. A technically fast website improves your visibility in organic search. Performance and SEO are therefore not separate disciplines, but two sides of the same coin.
Technology that really delivers under the hood
Performance issues rarely stem from a single error. They result from many small factors: uncompressed images, blocking JavaScript, a lack of caching strategies, and slow server responses. We analyze your website using professional tools, identify the biggest bottlenecks, and systematically resolve them. In doing so, we optimize not only load times but also rendering speed and interactivity. The result is a website that runs smoothly from a technical standpoint and offers your visitors a noticeably better experience.
Fast loading times are the result of many technical adjustments. From image formats to code quality to server configuration: every area contributes to overall performance. The following areas highlight where the greatest opportunities for improvement lie.
Core Web Vitals
Google's three metrics—Largest Contentful Paint, First Input Delay, and Cumulative Layout Shift—measure how visitors experience your website. We specifically optimize all three metrics to ensure your site meets the thresholds and benefits in search results.
Image Optimization
Images often account for more than half of a page's file size. We convert them to modern formats like WebP or AVIF, use lazy loading, and serve responsive image sizes. This allows pages to load faster without compromising visual quality.
Code Optimization
Unnecessary CSS, blocking JavaScript, and bloated HTML slow down page loading. We remove dead code, minify resources, and ensure that critical content loads first. The result: leaner page source code and faster render times.
Caching and CDN
Browser caching, server caching, and content delivery networks reduce the number of requests and shorten the distance between the server and the visitor. We configure caching rules tailored to your setup and, if needed, integrate a CDN that delivers your content quickly worldwide.
Database Optimization
Dynamic websites rely on database queries. Slow queries slow down every page view. We analyze query patterns, create indexes, remove outdated data, and implement query caching. This speeds up pages with a lot of content or complex filter functions in particular.
Performance Monitoring
Optimization isn't a one-time project. New content, plugins, or traffic spikes can affect these metrics. We set up ongoing monitoring to track load times and Core Web Vitals. This allows us to identify any deterioration early on and take targeted corrective action.
These companies know how we work
Google evaluates websites based on three measurable metrics: Largest Contentful Paint measures how quickly the largest visible content appears. Interaction to Next Paint tracks how responsively the page reacts to clicks and user input. Cumulative Layout Shift checks whether elements shift unexpectedly during loading. All three metrics directly influence Google’s ranking and can be viewed in Search Console. We measure your current metrics using field and lab data, identify the causes of poor scores, and implement targeted optimizations. Often, the problems stem from hero images that are too large, unused JavaScript, or missing size specifications for media files. Especially when it comes to UX/UI design and site architecture, these improvements have an immediate impact on the user experience. The end result is a green Lighthouse score that holds up in real-world use. A performance optimization agency focuses on these three metrics; everything else follows from there.
„Working with an agency requires good ideas, cutting-edge technology, and clear budgets with no surprises. But the personal chemistry has to be right, too. With seitenweise, everything was just right. It was really fun.“
Mathias Schwaben
Intervideo
„To me, having a strong partner is important. Someone who is “passionate” about their work, who offers well-reasoned professional objections but also accepts and continues to fully support my decisions as a client when I choose a different path. I’ve been working very successfully with seitenweise in this way for many years—both in day-to-day operations and on many large-scale projects.“
Veal from Martina
Liebich & Partner
„seitenweise is one of the few agencies that has managed to completely exceed our expectations. Performance, quality, reliability, timing—everything is top-notch! Highly recommended.“
Florian Nack
myflexbox
„What particularly impresses us about Seitenweise is not only its technical expertise, but also its proactive approach.“
Dirk Bockelmann
DFT
„Working with an agency requires good ideas, cutting-edge technology, and clear budgets with no surprises. But the personal chemistry has to be right, too. With seitenweise, everything was just right. It was really fun.“
Mathias Schwaben
Intervideo
„To me, having a strong partner is important. Someone who is “passionate” about their work, who offers well-reasoned professional objections but also accepts and continues to fully support my decisions as a client when I choose a different path. I’ve been working very successfully with seitenweise in this way for many years—both in day-to-day operations and on many large-scale projects.“
Veal from Martina
Liebich & Partner
„seitenweise is one of the few agencies that has managed to completely exceed our expectations. Performance, quality, reliability, timing—everything is top-notch! Highly recommended.“
Florian Nack
myflexbox
„What particularly impresses us about Seitenweise is not only its technical expertise, but also its proactive approach.“
Dirk Bockelmann
DFT
STABL
STABL ansehen
Schmidt
Schmidt ansehenFrequently
Asked
Questions
Performance
First
We'll get your Core Web Vitals into the green zone
seitenweise is a digital agency based in Bielefeld, founded in 1999. We have over 100 clients and have completed more than 500 projects, many of which focus on technical optimization and website performance. We work where load times, Core Web Vitals, and server configuration make all the difference: at the technical foundation of your website. From analysis through implementation to ongoing monitoring, we support the entire process. In addition to performance, we offer web development, SEO, UX/UI design, and web hosting. For us, performance isn’t just an add-on—it’s an integral part of every web development project.
Marcel and André are your points of contact at seitenweise. They'll be happy to answer any questions you may have about performance optimization.
Your website could be faster. We'll show you where the biggest opportunities lie and how you can achieve measurable results in just a few weeks.