Meet the world of code sniffing with Denis Žoljom

Denis Žoljom talking about coding standards

Denis Žoljom is WordPress Engineer at Infinum, a design and development agency from Zagreb, Croatia. He has a strong passion for physics, writing development tutorials and lately, reviewing WordPress themes.

We’re looking forward meeting you at the beginning of September in Zagreb. Can you tell us a little bit about yourself?

Thanks, I’m looking forward to giving a talk at WordCamp Zagreb. My name is Denis Žoljom, and I’m a WordPress Engineer at Infinum, a design and development agency from Zagreb. My first passion was physics, which is why I attended and finished physics at Faculty of Science in Zagreb, but I realized theoretical physics wasn’t meant for me. I dabbled a bit with web development while at university, which is probably why I applied for a web developer position three years ago. That is basically where my WordPress story began. At first I worked on theme development, but later on, I started working with clients both at my job and privately.

Working on challenging tasks was encouraging me to learn more and more about how WordPress works, so I decided to write tutorials on my site – This, in turn, forced me to really understand the subject matter better which advanced my knowledge even more. Last year, after WordCamp Split I decided to get more involved in the WordPress community, so I started reviewing themes on and helped out with some projects maintained by the WordPress Theme Review Team like the theme sniffer. All that hard work paid off when I got invited to an interview at Infinum, which I knew was one of the best IT companies in Croatia. Getting a job at Infinum was a huge accomplishment for me, and I can say that I learn something new almost every day.

We have seen that you often publish tips and tricks for developers and average users on your website, Made by Denis. You are also building plugins like Simple linked variations for WooCommerce and publishing them on What motivates you to develop plugins? Do you keep track how many people are using your plugins?

Sadly I didn’t publish a tutorial for some time now. I need to find time to write a good tutorial, but I already have one coming up, so I hope I’ll start writing again soon. Initially, I started writing tutorials based on questions I found on Stack Overflow, and ideas for plugins came mostly from working with clients. WordPress is a mature software, and there are thousands of themes and plugins out there, so it’s hard to find something that hasn’t been done already. My first plugin is a result of working on a theme for ThemeForest.

At my previous job, we worked on an event theme that used The Events Calendar plugin, so I had an idea for extending it. My second plugin was created because a client asked me if I could find a way to link variations in WooCommerce so that you can hide one variation based on the value of the other variation. So it comes down to recognizing a cool idea that could be useful and creating a plugin out of it. I keep track of support for my plugins. Since they are rather specialized plugins, I don’t have that many active installs, and I guess since I basically have no support issues, the code quality is there. 😀 I check my profile page now and then and check the stats counter, but that’s mostly it. Since I don’t make a living out of them, I don’t spend too much time advertising my plugins.

Rest, relaxation and inspiration time

How did you start your WordPress journey? What has encouraged you to speak at WordPress meetups and connect with others in the community?

As I’ve mentioned in the first question, after graduation I tried applying for jobs that physicists who aren’t pursuing science usually apply to: banks and financial institutions. Luckily for me, that was a bust, so I ended up in a firm that was developing WordPress themes, and that’s how it all started.

What encouraged me to be more included in the WordPress community was WordCamp Split. The whole atmosphere there was just positive, and I said to myself: I would really like to talk at a conference like this. It would be so cool to be a part of such a community. After that, I started to get involved in theme reviewing. I submitted some patches to the core and meta and wrote tutorials. Just giving back to the community and being a part of it felt really good. I also gave a talk at a WordPress meetup in Zagreb, which was related to the talk I’ll be giving at WordCamp.

Do you think that some colleagues in our industry sometimes neglect the quality of the code just to finish the project ASAP? Should WordPress community focus more on familiarizing developers with WordPress Codex?

My talk is aimed at developers. I will be covering two main topics – coding standards, with emphasis on WordPress Coding Standards, and automation in code checking using linters and PHP_CodeSniffer. I think that this is especially interesting for theme developers because theme review (at least on can be a long process. And if you follow coding standards and best coding practices, it can help you speed up that process. On the other hand, when working in a team of 3-5 or even more people, it’s important that the coding style is consistent throughout your project. Having automated checks can help you with consistency and code validity.

WordPress Codex is a good place to find out how certain things can be done in WordPress, especially if you are a beginner. It has one flaw in that it was maintained by random people (I don’t think that the Codex is updated anymore), so you couldn’t really be sure if an example given there is the best one. That is why I encourage people to use Developer Resources, and especially code reference. Especially because the code reference is pulled from the WordPress core. This means that any core changes will automatically be reflected on the code reference. You can see what a function does, and, for instance, see if there are some useful filters that you can exploit to your benefit. Furthermore, knowing how something works makes you a better developer. And there are examples in almost every reference. I think that the community should guide developers to familiarize themselves with the Developer Resources because it has all the handbooks and code references that will definitely help you get to know WordPress in a better way.

Did you get your ticket?

If you haven’t already, get your ticket for WordCamp Zagreb today. Tickets are priced at 20€ (around 150 HRK) which will give you entrance to the conference, (first) access to workshops on Friday and to Contributor day on Sunday. You will also get the drinks, lunch, incredible t-shirt and other cool swag from our sponsors.

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