What is COSCUP

COSCUP is one of the biggest open source conferences around Asia. It is an annual conference that has been held by the open source community since 2006 and acted as the major advocate of the free open-source software movement (FOSSM) in Taiwan. COSCUP is composed of talks, sponsor and community booths, and BoF (Birds of a Feather) meetings, targeting to serve as a platform to connect open source developers, users, and promoters to break away from the common misconception that traditional commercial software developers rarely interact with their users. 

In addition to overseas speakers, a great number of local open source contributors in Taiwan proactively gave their talks here to share their thoughts and findings. Developers, users, and promoters form the essence of an open source ecosystem. COSCUP is held for these three roles to embody the spirit of the open source community. 

Source: Official COSCUP Facebook page

LINE Taiwan x COSCUP 2019

COSCUP 2019 was a two-day event that took place from August 17th to 18th at the National Taiwan University of Science and Technology. It had more than 1600 passionate participants and 200 proactive speakers with 15 talk tracks rolling simultaneously. As one of the Diamond sponsors, members from LINE delivered 5 talks, including the keynote and 4 talk tracks. Each of our speakers attracted strong responses from the audience with insightful sharing and distinct charisma. Also, we organized company booth to engage COSCUP participants with periodic talks about LINE services, engineering job content, and LINE engineering culture, delivered by more than 10 engineers from LINE Taiwan, LINE Fukuoka and LINE Pay.

Beyond all the appealing sessions, we collaborated with the Armeria team to host the first LINE BoF for COSCUP participants who were interested in developing large-scale web services after day one of the conference. Also, we were more than glad to meet the NAVER Pinpoint open source project team that gave a powerful lightning talk. For COSCUP 2019, we provided a total package of the LINE experience, from talks that influenced hundreds of participants. to the meetup that where LINERs engaged with other open source developers in depth! 

Keynote and talks

For this year’s COSCUP, we had 5 speakers from LINE Taiwan, Japan, and Korea. A large audience poured in to obtain first-hand information about LINE’s achievements and efforts towards open source development.

LINE Open Up / Evan Lin

Evan Lin, LINE Taiwan Technical Evangelist, delivered a keynote speech with the topic “Open-up LINE” to introduce all LINE platforms and LINE open-source projects. The speech aimed to help participants understand that LINE was not only a messaging platform company but a major contributor to all sorts of open source projects. LINE had established more than 50 open source projects. On top of software development tools for the messaging platform, useful packages had been provided to develop LINE projects, including well-known open source projects such as Armeria and Central Dogma. LINE had also taken the initiative to collaborate with relevant open source communities to foster the ecosystem as a whole. 

This speech shared LINE’s internal open source project development flow, introduced the essence of LINE engineering culture, and engaged the developers to take part in open source project development with an open mind.

MySQL at LINE / Kentaro Kitagawa

Kentaro Kitagawa, LINE Japan database administrator, talked about MySQL operation at LINE in this session. As LINE manages thousands of MySQL instances and new services are released on a weekly basis, the number of database instances grows daily. Kitagawa showed the participants how to manage the thousands of instances effectively and how to approach MySQL 8.0 and so on.

Armeria: The Only Thrift/gRPC/REST Microservice Framework You’ll Need / Trustin Heuiseung Lee

Trustin Lee, the founder of Netty, introduced Armeria, a microservice framework. Armeria was unique because it had Netty-based high-performance HTTP/2 implementation, let the developer run gRPC, Thrift, REST, Servlet web app on single TCP port in single JVM, and integrated Spring Webflux and Reactive Streams.

How to Make an IoT Device that Can Be Combined with LINE / Hazel Shen

Hazel Shen, LINE Taiwan software engineer, introduced LINE Things platform and showed how to make simple IoT devices using ESP32 and a Raspberry Pi. The goal was to connect the IoT device to the LINE app. In addition to displaying the code and devices used, Shen provided some examples of how LINE Things can be used in people’s daily lives. 

My Experience with Rancher Pipeline / Wei Wan

Wei Wan, LINE Taiwan software engineer, shared his experience in using a Rancher Pipeline as well as the advantages and disadvantages of related tools. Currently, more and more projects are deploying its development and formal environment on K8S. The efficiency of cascade CI/CD pipeline had a direct impact on the productivity of a team.

LINE Booth

We set up a company booth to serve as a hub that connected COSCUP participants with engineers and members of Developer Relationships, PR, and HR. More than 10 engineers from different teams in LINE Taiwan and LINE Fukuoka gave short talks periodically to introduce LINE services, engineering job content, and LINE engineering culture (link in Chinese). We also invited LINE Pay to introduce their service and platform. Every time the talks started, the crowd would gather around LINE booth and then stay for further discussions with LINERs. The booth successfully engaged the participants and answered questions with in-person interaction. 

Highlights of the day


We collaborated with the DX part team closely to host the first Armeria BoF (Birds of a Feather) in Taiwan after the first day of the conference. Over 35 participants showed up and had a great time networking and listening to case studies for adopting Armeria. The following topics were covered in the BoF:

  • Self-introduction of all, including DX Part team and all participants
  • Lightning talk from DX Part team members
  • AMA (Ask Me Anything) from the participants

After the self-introduction, the atmosphere was perked up with the warm interaction among the enthusiastic participants and awesome hosts. The brief yet powerful lightning talks then brought Armeria and the LINE open source program to life from various perspectives, including the open source culture in LINE, the concept of Armeria and Central Dogma, the adoption of Armeria, and personal stories about “how I became a full-time open source developer at LINE”. In the AMA session, participants genuinely shared their questions and feelings that raised laughter and thoughts at the same time. The BoF was wrapped up with heated discussions. Everyone left with smiles on their faces after this fruitful night. 

NAVER Pinpoint Team Lightning Talk

NAVER Pinpoint open source project team members Roy Kim and Hyun Jeong gave an appealing lightning talk to cover how Naver used Pinpoint to monitor their services, giving the audience some insight on how to troubleshoot problems in a distributed environment.

Community Booth for

The Taiwan Developer Relations team had been collaborating with the Chatbot Community and hosted lots of meetups over time. In COSCUP, we co-worked with the chatbot community to have community tracks with LINE developer Hazel Shen promoting LINE Things to all participants. 


It was my pleasure to take part in COSCUP 2019 as a LINER and experience the passionate and dynamic vibe of open source community. One of LINE’s missions is to foster the open source development community, and the enthusiasm and persistence towards advancing the ecosystem of open source shown by the community deeply inspired me. I am looking forward to what they will come up with next year at COSCUP 2020!

Follow the official LINE Developer Community account (@line_tw_dev) now to receive notifications about meetups or the latest news about our developer programs.

About the LINE Developer Community Program

LINE launched the LINE Developer Community Program in Taiwan at the beginning of this year. We invest in human resources and resources over time to host a wide range of online and offline events; including community meetups, recruitment day, developer conferences, and so on for developers. More than 30 events will be held. Readers are welcome to continue checking the latest status for events. For more details, please refer to the LINE Developer Community Program Calendar (link in Chinese).