summer homework

Introducing Rekcurd for Clova

Machine learning (ML) is getting more and more popular these days. You probably are using it already at your work, or have been encouraged to have a go at it. Thanks to its popularity, we see more tools and frameworks for machine learning emerging. Not only that, anyone can learn linear regression, logistic regression as well as various deep learning algorithms such as Perceptron, Adaboost, Random Forest, Support Vector Machine and XGBoost. Although we are seeing growth in tools and frameworks for learning, there are not enough tools or frameworks for operating machine learning modules. Which brings me to introduce a machine learning management platform, Rekcurd, we use for the LINE’s AI platform, Clova.

Making a Flex Message with LINE’s Go SDK

Hi there, this is @sugyan (Twitter, GitHub) from LINE Kyoto office. This was first time for me to experience  Kyoto’s Summer, and boy, was it really hot or what!? (The original post in Japanese was published in August 2018.) In June 2018, a new message type, Flex Message, was introduced in the LINE Message API, allowing more complex […]

Write you a webpack for great good

Module bundlers have become quite popular in the world of JavaScript. Today, I’d like us to briefly see the concept of it, get into how it really works, and I’ll share the story of making a module bundler myself.

What is a module bundler?

Module systems structure a large-scale code base into units of modules. For long, there has been no module system for JavaScript, but ever since Node.js started to use a module system called CommonJS from 2009, modular programming became a common practice. Also, ES Module, a new module system, has been added to the JavaScript specification in the ECMAScript 2015. It’s hard to imagine coding JavaScript without modules nowadays.

Combining Slackbots into one, with gRPC

Hello all! I am suzuki-shunsuke from LINE IT Strategy team who is in charge of developing and running internal systems. Today, I’d like to share how I merged multiple Slack bots into one using gRPC.

How it all began

These days, my main tasks as a member of Slack management team, are making and operating slack bots at LINE. One day, we got a request to combine the bots we use into a single bot, for the following reasons:

  • Inviting numerous bots into a chat is a fuss.
  • Knowing all the bots available is difficult.
  • Adding more functions to a single bot is better than adding more bots.


Hi, I am Okada(@ocadaruma), a member of the LINE Ads Platform team. I’ve been interested in Go’s GC (Garbage Collection or Garbage Collector) for a while, which got me even to write a post about it. Go is a programming language developed by Google and supports garbage collection. Go also supports concurrency through channels. Many companies, including Google, are using Go, and LINE also uses Go for developing tools and services.


Using Go, you can easily develop low-latency applications. Go GC seems much simpler than the runtime of other languages. As of Go 1.10, the garbage collector for Go is the Concurrent Mask & Sweep (CMS) collector which does not compact and is not generational. This is nothing like JVM.

Data system opens its doors to all Liners

This is Keiji Yoshida, a data engineer from LINE Data Labs. From 2017, our team has been working on building and providing a system where any Liner could access data of services they are involved in.

Have you heard of LINE Data Labs?

LINE Data Labs is a team supporting LINE services, with data; we expertise in collecting, processing, aggregating and analyzing data for each LINE service and provide our result to service members. About 50 members consisting of machine learning engineers, data scientist, data designers and data engineers work together to collect and aggregate data and provide BI (Business Intelligence) and reporting service for visualization. We help service stakeholders to make decision with analyzed data and continually seek ways to help them such as applying machine learning to services and so on.

サーバーサイドKotlinの知見/KotlinでClova Skill Award挑戦


LINE Engineering Blogをご覧の皆さまこんにちは!今日の記事は2名の連名によってお送りします。LINEでゲームプラットフォームを開発しているKagayaと、ライブ配信サービスLINE LIVEのAndroidアプリを開発しているakiraです。こちらはLINE Engineering Blog「夏休みの自由研究 -Summer Homework-」の9日目の記事です。

Using Headless Chrome with chatbots

Hi again, this is Nakajima, LINE’s Developer Advocate.

Be smart in using web with chatbots

I am sure you’ve had at least one or more encounters with the following and ended up with frustration:

  • Entering something in on mobile-unfriendly websites
  • Having to sign in every time you access a webpage
  • Entering something in on smartphones itself

LINE the app is mostly used on smartphone, and this is why we value and put much effort into UX. Having been frustrated myself, I wondered how LINE could ease up the use case I’ve mentioned earlier and tried out something that has never been done before. Which I’d like to share with you in this post.