Magazine WEB+DB PRESS Vol.133: Interview “The Challenge of Becoming a Server Engineer from a Client Engineer” by Daisuke Okada
※This article is machine translated.
Explore Cocone’s engineering capabilities to open up a new era of Web3
Top-level performance in the world’s favorite digital world
Part 1: The Challenge of Becoming a Server Engineer from a Client Engineer
Cocone, a widely developed social service that coordinates characters, released “PKCL Twins” for the Asian market in November 2022. It is a blockchain service version of the popular “Pokecolo series”, incorporating new technological elements such as Web3 and NFT. We asked Daisuke Okada, who was involved in the server side of the service release, about the details of the new technology implemented and how the environment was constructed.
New service “PKCL Twins” incorporating Web3 and NFT elements

– Please introduce yourself.
I am Daisuke Okada, PKCL Twins Project, Cocone Corporation. In my previous job, I developed embedded systems as a software engineer for commercial multifunction devices. I joined Cocone 7 years ago. At first, I developed applications as a client engineer, but from 2022, I joined the development of “PKCL Twins” and am challenging myself to become a server engineer, which is a new area for me.
– What kind of application is “PKCL Twins”?
It can be called a blockchain service version of the “Pokecolo series”. “Pokecolo” is a popular application (avatar service) released by Kokone in 2011, in which users enjoy communication by dressing up cute characters and coordinating their rooms. PKCL Twins” is based on “Pokecolo Twin” of this series and takes on new challenges such as global development, Web3, and NFT. This is the first service at Cocone’s headquarters to adopt NFT.
“PKCL Twins” started its global service on November 29, 2022. By the way, “PKCL” comes from “Pokecolo”, which also means “Pop, Kawaii, Cool, Lovely”, which is the theme of the service.
In “PKCL Twins”, as in “Pokecolo Twin”, you can not only enjoy coordinating your characters, but you can also NFT your coordinated sets. There are other services that allow users to develop characters and collect items, but if the service is terminated, the characters and items may no longer be accessible. However, by converting to NFT, it is not only possible to keep them permanently, but also to identify the owner and the value of the assets, and to sell them on the NFT marketplace “Jellyme” operated by the Cocone Group. This service is at the cutting edge of digital assets.
Building infrastructure for global expansion and blockchain
– You are currently a server engineer, what did you do for “PKCL Twins”?
These include the establishment and maintenance of multilingualization mechanisms (currently only English, but expected to increase in the future) and the environment around the infrastructure for global expansion. Cocone’s avatar service has 130 million customers to date, and since “PKCL Twins” will be deployed in Southeast Asian countries, we are preparing the environment with the expectation that many customers will use the service beyond national borders. For example, we are using AWS ECS for containers and AWS Global Accelerator to facilitate flexible scaling as the number of customers increases.
– What is the blockchain used by “PKCL Twins”?
“PKCL Twins” uses “MOOI Network”, a blockchain developed by a Cocone group company that specializes in the metaverse area, and which was just officially released at the end of June 2022.
Although transactions in “MOOI Network” have a speed suitable for transactions in the digital world, in order not to cause delays in everyday play, we have built a mechanism that directly accesses the application’s servers when customers use functions such as everyday dress-up. This eliminates the delays that tend to occur with blockchain. The blockchain is only used when items are converted to NFT, for example.
– What are some of the initiatives in server development at Cocone?
Is it that you are building the server in Go language (golang)? Since around 2019, Cocone has adopted the Go language for server development of “Pokekoro Twin”. Until then, Cocone’s server development was mainly done in Java language, but now we are developing servers using Go language and Kotlin. Server engineers who mainly use Java language have also learned Go language, but there is a culture of sharing between engineers, so the knowledge level of all server engineers at Cocone has increased.

Generally speaking, the Go language is not as free as Java, or it is said that it needs to be written in a certain way. On the other hand, Go is simple to write. It is a language that can be learned relatively quickly and is easy to handle once you get used to it.
With Go language, you can build a web server with only basic functions. I did not use a framework (for building a web server) because Go is a language I am familiar with and it requires only a short code. Besides, the Go language has the advantage of parallel processing and fast execution, which makes it easy to achieve the performance of the server.
Job change, starting over from level 1.
– You were a client engineer and now you’ve applied to be a server engineer.
At first, I was somewhat apprehensive. I had wanted ” work on the server side since I joined the company, but I had been doing client-side development for a long time, so there was some resistance. I decided to take the opportunity of moving to “PKCL Twins” to try a job change. However, I feel as if I am starting all over again from level 1, even though I have been working at a higher level. I was even disappointed when an engineer much younger than myself pointed out my mistakes (laughs). But at Cocone, we exchange information through study groups, regular engineer meetings, and Slack, so it’s easy to see who knows what, and it’s easy to catch up on technology.
– What do you like about Cocone?
At first, I was somewhat apprehensive. Since joining the company, I had a feeling that I wanted ” try (server-side development as well), but I had been doing client-side development for a long time, so there was some resistance. This time I joined “PKCL Twins” where human relations are relatively flat, and it is easy to express your opinions even if you are a supervisor or a subordinate. Also, as is the case with the development of “PKCL Twins”, we are actively adopting new technologies, so as an engineer I can be involved in the cutting edge. This is an environment where you can take on new challenges if you want to. If you have a spirit of challenge, this is the place for you.
– What direction do you want to take your career in the future?
In my previous job, I used NetBSD, C, and Java in embedded control systems, and since coming to Cocone, I have been a client-side engineer for 6 years, learning Cocos2d-x, Unity, React Native, C++, C#, TypeScript, and since 2022, Go language on the server side, I have mastered Go language, MongoDB, and Redis on the server side since 2022. I am proud to say that I now have a fairly broad technology stack, but I would like to continue to improve my skills. However, regardless of whether I move on to the client side or the server side in the future, I hope to improve the service from the customer’s point of view.
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