Hi, my name is Hidenari Tajima ( @clockvoid ). I am an Android app engineer at DeNA. DeNA supports various meetups and events in our office lounge. Today, I would like to share my experience with one of these events: the 7th meetup of Mobile Dev Japan.

About Mobile Dev Japan

First of all, let me introduce Mobile Dev Japan (MDJ below).

MDJ is a community for English speaking mobile engineers living in Japan. It is not limited only to fluent speakers: anyone looking to improve their English skills is also welcome.

Engineers in mobile engineering attend these meetups to socialize regardless of frameworks, so you can find iOS, Android, Flutter and React Native developers there.
Basically, MDJ is a place where you can improve your English while having fun discussing technologies you are interested in.

There is also a Slack workspace where participants communicate and share information about the next event. As of May 2025, the Slack workspace has exceeded 270 members, and is still growing rapidly! MDJ operates with a focus on building a community. The organizers are committed to create an opportunity for participants to connect with each other.
You can find more on their Connpass group .

In this article, I will share the atmosphere of the event, topics discussed during the LT sessions, and conversations I had during the networking party.

Event Flow

When they arrive at the venue, participants first write their name on a name tag sticker and stick it on their clothes. Participants are also encouraged to write the technologies they work on, to make it easier to start conversations with others.

The catering is open from the beginning of the event, allowing participants to enjoy light snacks and drinks while listening to the LT sessions.

Lightning Talk (LT)

This time, three Speakers gave a talk!

First LT：

The first LT was about Tramline , a release dashboard for native apps. It is open source and available on GitHub. The author of Tramline gave the LT himself, so it was a rare opportunity to speak directly with an OSS developer.

Second LT：

The second LT was about adding extensions to native apps. iOS has a mechanism called App Extensions, but Android has nothing exactly like that, so developers need to find other ways to achieve the same result. During the presentation, various methods were introduced, ranging from providing functions that can be used from other apps, to implementing GUIs as extensions.

Third LT：

The third LT Speaker talked about his own experiences since coming to Japan and his work. By the way, I recently participated and won a hackathon with this Speaker! He also talked about that during the LT.

Announcements

In MDJ, there is a time for participants to share information about their events or projects after the LT sessions. I took this opportunity to announce two meetups ( potatotips and Shibuya.apk ) I am planning to hold at the our company’s lounge. There were three other participants who also shared their announcements.

Networking Party

Finally, we had a networking party. MDJ organizers place great importance on this part of the event, because their main goal is to build a community. Participants naturally communicated with each other, just like at any other meetups, but additionally, the organizers actively approached participants who seemed to be alone, so there were few situations where someone was left out.

There are various topics to discuss, but I will share some examples of conversations I had.

First, I talked with some students about job hunting. There were two international students looking for jobs in Japan, so I offered them some advice. In Japan, many companies do not conduct interviews in English, which can be a significant challenge for international students. MDJ has student participants every time, I think it is great to have the opportunity to interact with them.

After that, other participants joined the conversation, and we started talking about my mobile phone. My phone is a Galaxy Z Fold 5, which is a foldable type of mobile phone.
Foldable devices are still relatively rare among the participants, so we had a lot to discuss. For example, we discussed whether I use it for development and when apps are likely to break. The Android framework triggers configuration changes when the foldable devices lids are opened, so if the developer doesn’t take account of that change, the app may behave as if it is broken.
Then, someone mentioned that the UI on Galaxy Z Fold 5 looks smoother than the iPhone’s. An iOS app engineer explained that while new iPhones like iPhone 14 Pro supports 120Hz, it generally runs at 60Hz and only switches to 120Hz mode during gaming.

Finally, I was able to talk to a few people I had spoken with at previous events. A guy I spoke with at the first event remembered that I had talked about Arch Linux. I was also able to reconnect with someone I had spoken with at the previous event.
Having people remember me and feeling part of the community made me really happy. The networking party is designed to allow participants to move around freely, so you can connect with various people throughout the event. This encourages participants to stay connected with those they met, creating a desire to meet them again.

There are many participants whose first language is not English, so we can share the difficulties of speaking and listening in English. This makes it a great event for those who want to practice their English skills and have a space to speak more!

Conclusion

In this article, I shared the atmosphere of the event, topics discussed during the LT sessions, and conversations I had during the networking party.
MDJ has a community that welcomes not only fluent English speakers, but also those who want to practice their English. If you are interested in MDJ, please join the Slack workspace to get a notification for the next event!

Additionally, in DeNA, we provide spaces to hold events like MDJ. If you are looking for a venue for your community or event, please feel free to contact a DeNA employee nearby!