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How and what front-end developers actually do at LINE?

Hello to the world! I’m Yeon-Eui Hong from Developer Relations Team. I’d like to take this opportunity to share the story of the LINE Developers Meetup held for the second time in Korea, on April 16, 2019. The theme of this meetup was “LINE front-end developers, what do they actually do and how?” I was proud to see all of the 120 available seats filled up at lightening speed, testifying to explosive interest from participants. 

In the course of preparation, I met with the members of front-end team at LINE to discuss about a theme for the meetup. Discussion started from a perception that many in Korea still thought of LINE only as a messenger app company and were not aware of its many other services. Everyone agreed to focus on LINE’s various services, especially what it does with web-based technology, on top of the famous messenger.

It was already time to welcome the participants as we set up the chairs and sandwiches. Neat LINE DEV stickers were very popular among the participants.

Many have wondered about what was shared at the meetup. Let me give you a quick summary of each session of the LINE Developers Meetup.


Web-based services and technologies at LINE

The first session was led by Seok Heo. He spent his share of time to introduce web-based services under development and the type of web-based technologies in use at LINE, whose main business is in servicing the native application. The following table lists up the web-based services offered by LINE. Some services are provided on the LINE messenger app in Korea, and some are available only in other countries such as Japan, Taiwan and Vietnam.

Web Service LINE Timeline Web
Hybrid Web App
  • LINE Search
  • LINE More Tab
  • LINE Chat App
MessengerLINE Chrome Messenger
Library & Platform & SDKLINE Social Plugin

The next slide shows LINE’s technology stack for web development. JavaScript is considered to be most important. Network and back-end technologies are also important pieces in the technology stack. LINE runs WAS (Web Application Server) with Node.js and Express for SSR (Server Side Rendering) and PM2 for node instance management. 

Most of LINE’s web services or applications are developed as a Single Page Application, using Vue.js or React and Node.js for SSR, if necessary.

Seok concluded his presentation with an emphasis that it was not a prerequisite to know the entire technology stack to apply for a front-end developer position at LINE. He explained that it was more important to know when to apply what technologies amid rapidly changing technological trends and have the passion and understanding of JavaScript basics.


How do front-end developers do their work at LINE?

Jungin Lim introduced how front-end developers do their work at LINE in the second session. He explained about project management methodology, development culture including code review and global project collaboration with developers in LINE’s overseas offices. It was quite impressive when he referred to front-end development team as a matrix organization, composed of professionals dedicated to front-end development and engaging in respective projects with ownership. Jungin also spent some time on code review, which is a must for the team. Code reviews are conducted via three channels: Git, meetings and pair programming.


Jungin even shared TMI — in a positive way — on respective development environment, IDE and keyboard used by each member. It was interesting to get a hint of personal preferences of LINE front-end developers.



Wanted: LINE front-end developers

Third session was presented by YoungKyu Choi, and it was about hiring process including coding questions and, more importantly, first-hand tips for those who were interested in LINE’s front-end developer positions. The team conducted dogfooding, and a total of 21 team members participated in dogfooding for five hours to test the level of difficulty or to measure the time to solve the questions. It required a lot of time and effort from the members, but they were willing to contribute for the cause of finding talented future colleagues. 


YoungKyu offered a critical piece of advice for potential candidates regarding what to write in the resume: Focus on what technologies you used instead of what was developed, pursuant to the minimum qualifications on the job posting.

I believe this session was all the more insightful for potential candidates as the advice came from actual front-end developers in the field, instead of HR team.



After all the sessions, Q&A session was held with questions left on sli.do by the participants during the sessions. Minwoo Park, who led this Q&A session, proposed to make today’s meetup a great networking opportunity and invited everyone to sit in a circle. People asked questions about LINE such as difficulties experienced by new front-end developers and discussed the latest front-end technological trends. I hope this meetup was a meaningful opportunity to shed light on what LINE’s front-end developers did and the kind of services provided by them.

I’ll wrap up this post with the following job postings for front-end developers. Have your hopes up high for the next LINE Developers Meetup!