MerZ IT-SerVice - Responsive web design, online shops, blogs and CMS

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Your constant partner throughout every phase of your eCommerce project: MerZ IT-SerVice has been creating, maintaining and extending eCommerce shop systems for over 15 years

Different default addresses for billing and shipping

NEW MODULE: consent to share data with parcel delivery providers in accordance with the GDPR for modified eCommerce

modified eCommerce Shopsoftware version 3.1.6 rev 16563 release

Custom development of modules, plugins and functional extensions for your shop system or content management system by MerZ IT-SerVice

Your e-commerce agency with over 20 years of experience

"Complaining about fierce competition is, in reality, merely complaining about a lack of ideas"
- Walter Rathenau

Intuitive - Creative - Innovative

Professional e-commerce solutions: We build your online success

For over 20 years, we have been your professional web agency for individual, bespoke solutions in e-commerce and e-business. We know what makes an online presence successful and use proven open source systems such as modified eCommerce Shopsoftware, Magento, WordPress and Joomla to turn your vision into reality.

We prioritise comprehensive advice, careful project planning and cost-effective implementation of your specific requirements. Our goal is to deliver a solution that works today and is ready for the future.

Usability meets search engine optimisation

We believe a successful online presence rests on two key pillars: usability and search engine friendliness. That's why, from the very start of your project, we ensure that the design and structure meet both your expectations and the needs of your visitors and customers. Intuitive operation, clear navigation and appealing content are the keys to winning over visitors and encouraging them to spend longer in your shop.

At the same time, we ensure that your online presence is optimised for search engines. Clean code, fast loading times and strategic keyword integration make your website easy to find on Google, Bing and other search engines. This gives you greater visibility, more organic traffic and, ultimately, more sales.

Ready for your project? Contact us!

Interested in working together? Want to realise your dream of running an online shop or take your existing presence to the next level? Then don't hesitate to contact us. We look forward to getting to know you and finding the best solution together.

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News Blog

PHP2Shell: critical PHP security vulnerabilities – act now

PHP2Shell: Kritische PHP-Sicherheitslücken – Onlineshopbetreiber müssen jetzt handeln

Operators of modified eCommerce shops should urgently check that their PHP version and shop are up to date.

Critical PHP vulnerabilities known as PHP2Shell have recently come to light which, under certain conditions, may allow remote code execution without prior authentication. In the worst case, an attacker could execute their own code on the web server and completely compromise a shop.

What is PHP2Shell?

The name PHP2Shell refers to two critical vulnerabilities in the PHP core: CVE-2026-109618 and CVE-2026-109619. They affect the PHP runtime environment used by numerous websites and online shops, rather than just a single shop application or extension.

According to the PHP project, the vulnerabilities may allow unauthenticated remote code execution. Affected systems include PHP installations that process web requests, including PHP-FPM, Apache with mod_php, php-cgi, FrankenPHP and LiteSpeed. In certain configurations, an attack can begin before the shop's actual application code is executed.

A particular concern is that exploitation does

read more ...

Dealer registration and VAT ID validation: B2B registration, guest customers and correct tax logic

Händlerregistrierung und UStID-Prüfung: B2B-Registrierung, Gastkunden und korrekte Steuerlogik

Many operators of modified eCommerce Shopsoftware shops sooner or later face the same questions: how can dealers be registered properly? How can a VAT identification number be validated reliably? And how can incorrect tax calculations be prevented when a guest customer from another EU country places an order with a valid VAT ID?

This is exactly where the two modules MITS Dealer Registration and MITS VAT Validation Extended from MerZ IT-SerVice come in. The modules address different tasks but are deliberately designed to work together, combining into a powerful B2B solution for modified eCommerce Shopsoftware.

The problem: guest customers with valid VAT IDs in modified eCommerce Shopsoftware

Guest orders are a particularly important issue. In many shops, business customers can place o

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Withdrawal button required from 19.06.2026

Widerrufsbutton-Pflicht ab 19.06.2026

Withdrawal button required from 19.06.2026 – what shop operators should know now

From 19.06.2026, an electronic withdrawal function will become mandatory for many online shops. For shop operators, this means that withdrawal must be possible directly online, easily accessible and properly integrated into the shop. Anyone running modified eCommerce Shopsoftware should therefore start considering a practical implementation early.

This is exactly where MITS Withdrawal Button Pro comes in: the module adds a structured digital withdrawal process to modified eCommerce Shopsoftware, with convenient frontend use, clear internal processing and flexible configuration options for everyday shop operations.

Why this matters now

Many shop operators are already familiar with the legally required order button at checkout. The new withdrawal button follows a similar principle: when a contract is concluded online, consumers should also be able to declare their withdrawal directly online.

In practice, this involves more than a single button: it re

read more ...

Be careful when copying code: why AI-generated code carries risks

KI-generierter Code birgt Risiken

The rapid development of artificial intelligence has revolutionised many industries, particularly software development. AI tools capable of generating blocks of code or entire functions are hailed by developers worldwide as efficiency boosters. Yet this apparent convenience conceals significant risks that companies and developers often underestimate. Experts warn against adopting AI-generated code uncritically, as this can cause serious security vulnerabilities and unexpected problems.

Lack of context and security awareness

The main problem with AI-generated code is its fundamental lack of contextual understanding. An AI is trained on vast amounts of data from public repositories, forums and tutorials. It learns patterns and writes code that appears statistically "correct". What it does not understand, however, is the specific requirements of a project:

Security requirements: an AI cannot distinguish between secure and insecure coding practices unless it has been explicitly trained to do so. It knows neither a company's individual security policies nor the specific threats an application faces. This can unintentionally introduce vulne

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eCommerce

Benefit from more than 20 years of experience in eCommerce. We create, maintain and extend your eCommerce solution to your individual requirements. We rely on proven open-source systems such as modified eCommerce Shopsoftware, Gambio and Shopware.read more

Blogs and CMS

A modern online presence should no longer be a static and inflexible website. Up-to-date, dynamic content is important for every successful website. With a blog or CMS such as WordPress or Joomla, dynamic websites can be maintained quickly and easily and new content can be published at any time.read more

Web design

Do you need a new web design for your website, online shop or content management system (CMS)? You are in the right place. Whether responsive or adaptive web design with HTML5, CSS3 and JavaScript, we create your individual design tailored to your target audience. Feel free to contact us directly!read more

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