How to improve a performance of your web service?

Before I begin…

Recently, I have been working super scrum mode with my team to create an internal service that basically collects the data or analysis provided by security engineers. Because speed was a key factor in this project, we chose tech stacks with speed as a higher priority and this resulted in more familiar tech stacks of the developers in the team while sacrificing engineering perspectives. Luckily(?), I soon was able to see some of the critical issues and one was the performance. The speed discrepancy from local and dev…

How many articles have you read about the promise in Javascript?

Promising picture of promise in JS

If you are working or learning javascript relevant frameworks, it is natural to encounter a concept called Promise in javascript. What is a promise and why does it occur so often in JS? Before we move on to details of it, I want to briefly discuss background of how we may encounter such concepts.

Let’s assume that we built an e-commerce website. From the initial page after logging in, the user is able to see the current hot deals(recommended) products, my selected products, and other products. …

How do we choose sql or nosql when architecturing the backend or the database?


We learned that SQL is a relational database called “RDBMS” whereas NoSQL is non relational database. Because they are two opposite sides, I was mislead to a point where I understood both well. Theoretically, I was correct. But practically, I realized I was not near close to understanding both.

Before I share my story, let’s begin with theoretic terminologies a little more deeper.

SQL (Relational Database)

  • save data to a table with already defined data schema
  • through relationships, data are distributed through other tables

Data are being saved in…

how to write clean code in vuejs?

Cleaning the Vue

It has been about a month since joining a new IT company and have been enjoying the era a lot. When developing a service, developers often times disregard the importance of clean codes and following the proper conventions because of tight due times, lack of resources, and etc. However, clean code and following the conventions are important for several reasons.

1.Efficient in a team work for both readability and debugging

2. Using the frameworks/libraries in a intention of the creator to maximize of its pros

Therefore, I wanted to explore more on how…

TIL: RUN 2out of 3 learning Java


Inheritance, probably is one of the most often heard terms especially in Java. The idea is simple that a class inherits from another class to reduce the amount of the code and reinforce the reusabilities. For instance, if we had defined a class Car, we can simply create Porsche, and BMW class which would have different series such as Panamera or X5. What should we consider when we use inheritance in Java?

Visibilities demonstrate which properties to be exposed in different classes.

visiblities in Java

As shown above, private modifier (obviously) has the most restrictions in…

TIL: RUN 1 out of 3 learning Java

So, my main tech stack has been frontend just because I remember hating taking lectures with C/C++ and all those other statically typed languages. On the other hand, dynamically typed languages such as python and javascript attracted me because I could get right into the coding rather than understanding background of static checks and etc. Anyways, now I am aware of python and Javascript fairly well enough but the problem is, I still need to get back to those statically typed languages and learn them for being a full stack. So, I…

what is vuex? vuex?

Vuex is a library mainly used for VueJS and is used for managing states in complex component structure in application. Let’s read the “official definition” of vuex.

Vuex is a state management pattern + library for Vue.js applications. It serves as a centralized store for all the components in an application, with rules ensuring that the state can only be mutated in a predictable fashion. It also integrates with Vue’s official devtools extension (opens new window)to provide advanced features such as zero-config time-travel debugging and state snapshot export / import.

Let’s begin with how our web…

What needs to be considered when building backend with Node.js?

Let’s explore how to build backend system with Node.js. Before going deep dive on to the topic, I want to explain several important concepts so that we know the minimum amount of the terminologies/concepts when building the backend system.

What is REST API?

Baiscally we can say it is REST + API. The REST is Representational State Transfer and it is one of the types of software architectures for hyper media systems. The architecture refers to transferring the resource of the web via HTTP without complicated transfer layers. API is…

How to write backend with nodejs and express js

What is Node JS?

Nodejs is a javascript runtime built by Chrome V8 javascript engine. It is very light and efficient for using event-driven and non-blocking I/O models. It is following CommonJS modules and recently working on ES Module system but it is experimental. The one of the huge differences between Javascript in browser and Nodejs comes from the access of filesystem of Nodejs.

Nodejs Architecture(

As you can see, through the node runtime, the user is able to access node core and node API. Node API is a set of built-in modules…

Designing an uber backend — part I

When designing a complex(maybe not?) backend for a service, often one needs to come across a term called, “subscription.” Learning computer science at college, I personally did not know thoroughly about what it is and how it is being used because I never encountered a design problem like that by taking exams or school projects. But, the logic is integral in designing real service and want to summarize in very easy words and introduce several concepts relating to it.

Before going into the terminology, I want to update my step by step approaches…

Jimmy Gam

Hello, I am a software engineer in Tokyo. Any technical discussions are welcome so please contact me at

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