DAZN Engineering
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DAZN Engineering

CityJS London 2022! 🇬🇧

What is CityJS?

Born as a monthly meet-up of four different Javascript groups in London, CityJS has evolved to be an awesome conference organized by a non-profit organization founded by the community.

We can take a little breath because after a long pandemic, this year CityJS provided the in-person format in addition to the online one.

DAZN has been an important sponsor of the event and gave the opportunity to DAZNers to participate both online and in person. I had the opportunity to fly to London and it was a big pleasure to return to a real event after a long time, encountering old and new friends and for this reason, I would like to share my experience.

The format

The conference was on Friday 25th of March, but there were also some interesting workshops on the days before. It has been streamed online on the YouTube channel where you can enjoy all the talks. Sincerely, I missed the in-person conference and from my experience as a speaker, I found the conference so interesting!

The venue

Regent Street Cinema

The venue was the awesome Regent Street Cinema of 1848 located in the heart of central London and it is regarded as the birthplace of British cinema, where the first motion picture was shown in the United Kingdom. Beyond the cinema, there was also another big open space where some sponsors had their own stands, where everyone had the opportunity to meet new people talking about technology and anything else.


I was able to follow about ninety percent of the talks (sorry for those I left out). Following is a brief recap.

  • A Picture Worth a Thousand ProgrammesMaggie Appleton

She talked about the difficulties we encounter in understanding concepts expressed only by written text. Every day we discover new technologies and it’s always important to have also a graphic visualization of the concepts we are studying, helping us through the usage of cognitive metaphors. Even the “container” concept widely adopted nowadays is an example of a metaphor or even the “cloud” space. Linked to these concepts she brought the example of a visual explanation of the Node.js event loop of the famous video with more than 2M views, reflecting the importance of the topic.

  • Pay the Web ForwardAlex Lakatos

Do you know Web Monetization API? Alex talked about the possibility to make money in an open way using HTML code.

The API is now only a proposal on W3C Standard, it uses Interledger protocol and today the browser’s support is based on the usage of browser extensions. Alex explained the protocol from a functional point of view, explaining that it is used to move money from one bank to another without waiting hours or days and it’s particularly useful also for micropayments.

If you want to go deeper, here are:

– the draft: https://webmonetization.org/specification.html
– more info: https://www.w3.org/blog/2019/09/w3c-interview-coil-on-interledger-protocol-and-web-monetization/

  • Navigating the npm Ecosystem in the EnterpriseBeth Griggs

Beth works in RedHat and she is a Node.js TSC member. She shared her experience on how managing the complexity of navigating the endless NPM ecosystem, choosing the right module attempting to predict future trends.

We usually chose some modules, based on some considerations: the knowledge base you have inside your company, or if you have already worked with some component, or other times you can choose the newest technology just to learn something new. She explained how they managed the challenge inside RedHat.

  • Augmented Reality in the WebAda Rose Cannon

Is there something newer than WebXR? So interesting, in my opinion, to see how this technology will evolve and the future applications that could result in impacting our daily life. With the appropriate API, you are in control of compatible hardware devices, controlling their sensors and display in order to render 3D scenes for presenting virtual/augmented reality. She showed us:

– how to easily start with it using A-Frame web component to create a simple 3D environment
– you can create your 3D model, even if it’s difficult because you need some specific skills
– how to apply light effects, how to resize objects
– how to simplify your work using external libraries already available

  • PWAs: the new frontierDiego Gonzalez

Have you ever heard about Progressive Web App? Definitely. Personally, I learned what it was some years ago, and then, to be honest, I haven’t heard about it in a long time. But I discovered that there’s been a lot of work on it and it was a pleasure to be updated with the latest information by Diego. He shows us all the features (such as File Handling, Shortcut, Web Share API) PWA provides today and the relative supported platforms: Linux, Apple, ChromeOS, Android and Microsoft ecosystems. Today the reference environment is the Desktop.

  • GraphQL caching demystifiedMatteo Collina

Matteo, a Node.js TSC member, started his talk by explaining the benefits of different open source projects: Fastify, Mercurius, AutoCannon, Clinic.js and Undici. But simply speaking, the topic was about the performance improvements obtained by activating some cache techniques when you have to deploy GraphQL at scale.

  • The Risks of Micro-FrontendsRuben Casas

Everyone interested in Micro-Frontends needs to listen to this talk because Ruben talked about a so important aspect to be considered every time we embrace a new architecture or technology: think about it, if you really need it!

There are many frameworks today, especially in the Javascript world, so ask yourself if micro-frontend is the right choice for you: if you are a few developers in a small company, or you need to develop just a couple of services probably it’s not the right choice for you. Indeed, if you are a big company with thousands of employees, then you can enjoy the advantages. At the same time put attention to how to use the model: base your services by splitting them into domains and adapt the solution along the way.

Final Panel

The closing part of the conference was done with a great discussion panel headed by MC Max Gallo from DAZN. A panel is a sort of unprepared discussion between a group of people around a topic and managed by the Master of Ceremony MC whose job is to guide the conversation in the right direction.

It involved four different people, speaking about the Micro-Frontends architecture paradigm, and in my opinion, it was very interesting because you can listen to people who spent years in the field.

Max Gallo brings his big experience from DAZN, whose architecture is based on Micro-Frontends that scale on millions of users every day. In the end, all of them agreed on the same points: the importance of having loosely coupled components, the importance of a DX team inside a company to smoothly the work of developers, the importance of automation and the fact that if you are few developers probably it’s not the right choice, just because it adds additional efforts that you can take advantage only from a certain level of scale.


Thanks are due to DAZN, for giving me the chance to attend the conference and to visit DAZN London offices in Hammersmith, meeting some colleagues known only online until before! DAZN sponsored the CityJS and I think it’s very important to support and empower these types of events. By creating synergies between people, you can cultivate your network, it influences the company culture and this can be reflected not only personally and during the day of the conference, but even in the future, because sharing ideas can be the fuel for new projects, new improvements and last but not least to make new tech friends 😉

Are you thinking to start speaking at some conference? There are a lot of opportunities!
The next event is on the 16th of June: JSNation Amsterdam 🇳🇱 !!!




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Alessandro Polidori

Alessandro Polidori

Software Engineer @DAZN. Node.js, Javascript, WebRTC, VoIP, Linux & Conference Speaker. Travel and sport enthusiast !

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