Mercari Engineering Blog

We're the software engineers behind Mercari. Check out our blog to see the tech that powers our marketplace.

Android Lunch and Learn LT大会を実施しました 

こんにちは。メルカリでAndroidエンジニアをしているAtsuko (@muumuumuumuu) とMatthew (@callipan)です。 本日はメルカリAndroidチームで実施したLunch and Learn LT大会を紹介します。

I'm Matthew (@callipan) from the Mercari Android team. I'm co-writing this blog along with Atsuko (@muumuumuumuu) to introduce the Lunch and Learn Lightning Talk tournament that we recently held with the Mercari Android team.

Android Lunch and Learn LT大会とは


At present, we have a diverse team of about 30 Android engineers working in the Mercari Tokyo office, each with their own background and knowledge. In order to have a place to be able to share this knowledge easily within the team, we decided to hold a team meetup over lunch.


We opened a CfP within the team, and had talk proposals from engineers at manager level all the way to intern! Of these applications, we chose 4 that we wanted to hear at this first event.

実施の背景 | Implementation Details


Here in Tokyo, the majority of the Android meetups around are held entirely in Japanese, and so there are few chances to be able to either present, or listen to talks in English, and as such it is more difficult for non-Japanese speakers to share information. Here at Mercari the Android team is ¼ non-native Japanese speakers, and so we wanted to create a place where these English speaking members could easily attend, and easily share information, so we decided to hold this first event all in English. In the future, we would also like to hold more external meetups in English too, and so this lunch and learn event became a good place for non-native English speakers to practice presenting in English before a crowd as well, so overall it became a win-win.


Additionally, because this was an internal event, we were able to share information and source code directly that would be difficult to present externally, and so it was a great way to learn about the nuances of the code behind the various products.

当日の様子 | On The Day

今回は4人全員が英語で登壇してくれました。もちろん聴講側は参加者全員が英語での登壇を理解できるわけではないので、社内のGOT(Global Operations Team) に依頼しリアルタイムで翻訳をしてもらいました。 GOTはグローバル・コミュニケーションを推進するための組織です。

This time, we had 4 speakers present in English. Of course, it is hard to expect all of those listening to the talks to be completely fluent in English, especially as nervous speakers tend to speak even faster, so we enlisted the help of our internal GOT (Global Operations Team) to help with live translations of the talks into Japanese.

Our top batter @rkowase giving tips on how to add new features to existing screens.

RxJavaでUnit Testを書く時にエラーと戦いながら得たTipsを発表。
Next up is @sasamihoo talking about how to (correctly) test code using RxJava.

We then had @mootoh, giving us a quick rundown of the history of the Mercari Android app.

事情により資料の公開はありません 😇
Due to the nature of the content in the slides, we are unable to post them 😇

Finally, @rallat gave us a great talk about becoming the developer you want to be.

事情により資料の公開はありません 😇
Due to the nature of the content in the slides, we are unable to post them 😇

おわりに | Finally


All of the speakers’ LTs were really interesting, which made for a great event! Q&A also happened without a hitch, so we think we were able to better improve the communication throughout the greater team.


After hearing things from the speakers such as “It was a really great chance for me to practice presenting in English”, and from those in the audience saying “I want to have a go at presenting next time!”, stay tuned for the next time we hold this LT tournament!