How to cite:

Bernardus Redika Westama Putra and Evangs Mailoa. (2021).

Implementation Of Microservices In Fintech Applications Using Expressjs

Framework. Journal Eduvest. 1(7): 559-567

E-ISSN:

2775-3727

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https://greenvest.co.id/

Eduvest – Journal of Universal Studies

Volume 1 Number 7, July 2021

p- ISSN 2775-3735- e-ISSN 2775-3727

IMPLEMENTATION OF MICROSERVICES IN FINTECH APPLICATIONS

USING EXPRESSJS FRAMEWORK

Bernardus Redika Westama Putra and Evangs Mailoa

Satya Wacana Christian University

E-mail: [email protected], eva[email protected]

ARTICLE INFO ABSTRACT

Received:

June, 28

2021

Revised:

July, 9

2021

Approved:

July, 14

2021

Along with the development of software architecture, the

emergence of microservice architecture has become a trend

used by developers in recent years. This study aims to

analyze the implementation of microservices in Fintech

applications using the ExpressJs framework. The method

used in this research is descriptive qualitative method. This

study uses a library research method that refers to

resources available both online and offline such as:

scientific journals, books and news sourced from trusted

sources. The method used in making the application is

DevOps. In this method, there are eight stages of software

development, plan, code, build, test, release, deploy,

operate, monitor. Based on the discussion and testing that

has been carried out, several conclusions can be drawn

namely microservice makes application development

easier and more flexible by adding services as needed. Make

it easier for other applications to access services that have

been made via HTTP Requests, another thing is to facilitate

application integration between platforms, both mobile,

web and desktop.

KEYWORDS

Microservice, Devops, Applications

This work is licensed under a Creative Commons

Attribution-ShareAlike 4.0 International

INTRODUCTION

In this era, almost all activities that humans do are always dependent on technology.

The effect of the development of information and communication technology is to make

various fields experience changes, such as in the economic, social, and other fields which

 
 
Bernardus Redika Westama Putra and Evangs Mailoa 
Implementation Of Microservices In Fintech Applications Using Expressjs Framework
    560 
take place so quickly (Ngafifi, 2014). In this technological era, the financial sector is also 
developing  towards  a  more  practical  and  modern  direction  by  utilizing  technology 
(Rahadiyan  &  Sari,  2019).  Currently,  it  is  very  important  to  provide  technological 
innovation and its implementation in the economic field (Supriyanto & Ismawati, 2019). 
Business  people  are  starting  to  change  the  concept  of  business  to  digital  by  utilizing 
technology. All these changes are part of business competition. Technological development 
is a challenge that must be turned into an opportunity because it provides benefits in several 
aspects (Darman, 2019). 
With  the  rapid  development of  technology,  various  applications  in  the  financial 
sector  have  emerged  that  combine  financial  systems  and  technology  called  Financial 
Technology.  FinTech  is  an  application  of  digital  technology  that  is  used  to  provide 
solutions to public financial problems. Currently, Fintech has various functions and can 
develop more easily. Currently, Fintech has been able to serve many services such as e-
money, loans, fundraising, installments, and others (Muhamad Rizal, Erna Maulina, 2018). 
From  the  digitization  of  the  business,  there are  now  many  websites  and  mobile-based 
applications that facilitate transactions and payments without having to be limited by space 
and time as long as the smartphones and computers used are connected to the internet. The 
bigger the business that is run, the bigger the application that will be made. 
Rest  API  (Representational State  Transfer) is  a  style of software architecture  in 
which there are rules for creating services (Afifah & Setiaji, 2019). The HTTP protocol is 
always used for data exchange and data sent or received in the form of JSON (Rajagukguk, 
2018). This method is often applied in the development of an application, including the 
microservice-based application that we are currently developing. By using rest there are 
many advantages obtained, the  system becomes easier to develop in  the exchange and 
communication of data for better and faster performance. 
 A  web  service  is  a software system  created  to  support  interaction  between two 
different applications over a  network. The network  commonly used in web services is 
HTTP. Web services are also applications that are exposed or published so that clients can 
access or use data provided by web services (Perwira & Santosa, 2017). Web services also 
provide us with services to interact between web services. The URL or endpoint on the web 
service contains the required information and contains commands such as Get/Post and 
others. Web services allow clients to exchange data regardless of the type of database, the 
framework used. These factors make web services become widely used today. 
Along with the development of software architecture, the emergence of microservice 
architecture has become a trend used by developers in recent years. Microservice is an 
architectural style that separates large systems into small functional units to provide better 
modularity (Karabey Aksakalli, Çelik, Can, & Tek . Microservices provide 
flexibility  for  developers  to  develop  software  in  a  fast  time.  The  development  of 
microservice architecture is also supported by the lack of reliable monolithic architecture 
in dealing with system failures because in one application having the same codebase, it is 
certain that monolithic architecture is also a single point of failure that will occur if one 
service malfunctions or an error occurs. 
Microservice is a collection of independent and small services that have different 
functions and services (Rahmanda, 2018). These services can interact with each other to 
create a complex application through an API. This microservice consists of many small, 
separate services that focus on their respective tasks or functions in system development 
(Putra, 2018). 
Currently, many Fintech companies are starting to develop new businesses into the 
world of technology, and in the future, there will be more and more services that can be 
used.  Developers  must  use  the  right  method  so  that  application  development becomes 

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easier and more flexible and can be integrated into many platforms. The purpose of this

research is to produce a system design that can be easily integrated into many platforms

and make the development process easier and more flexible.

The research that has been done previously by (Ekasmara & Santoso, 2020) showed

that Microservice with JSON data exchange format provides ease of implementation to the

frontend. While ExpressJs itself is a framework owned by NodeJs which is deliberately

designed to be flexible and simple to help the backend application development stage.

ExpressJs is very different from other frameworks such as Laravel where this library is

given the freedom for developers to design applications in such a way that it is possible for

application developers to design software that is being built (Bachri, Priyambadha, &

Rusdianto, 2018). In contrast to previous research, this study aims to analyze the

implementation of microservices in Fintech applications using the ExpressJs framework.

RESEARCH METHODS

The method used in this study is a qualitative descriptive method. This study

uses library research methods that refer to sources available both online and offline

such as: scientific journals, books and news sourced from trusted sources. While

the method used in making the application is DevOps. In this method, there are

eight stages of software development, namely:

a. Plan

At this stage, planning for the manufacture and development of software is

carried out. After the planning is mutually agreed upon, then proceed to the code

stage.

b. Code

At this stage, the developer begins to create or develop software according

to the agreement in the previous stage.

c. Build

At this stage, the application that has been developed or made by the

developer will use the development server so that it can be used or tested by the

tester.

d. Test

At this stage, the software system will be tested by Quality Assurance to

ensure that the system is running well and look for bugs in the system to find out

the main problems by the developer. The software system will always be tested if

there are changes.

e. Release

At this stage, a system launch will be carried out with a focus on aspects of

change management, launch approval, and automation of system launch.

f. Deploy

After going through the testing process and getting the agreed results

without finding any bugs, the software system is built or deployed to the production

server.

g. Operate

At this stage, infrastructure installation will be carried out, infrastructure

scalability changes, infrastructure management and scalability will be carried out.

Bernardus Redika Westama Putra and Evangs Mailoa

Implementation Of Microservices In Fintech Applications Using Expressjs Framework

562

h. Monitor

At this stage, the software system that has been used by the user will carry

out monitoring to determine the performance or performance of the system.

Figure 1 Devops Method

RESULTS AND DISCUSSION

Figure 2. API Gateway Architecture

Based on Figure 2 in the depiction of the API gateway architecture, all client requests

are directed and then forwarded to the microservice according to the specified endpoint.

After the request from the client is in accordance with the provisions, the microservice will

send a response that will be directed to the API gateway again, then forwarded to the client.

Each microservice will have its own endpoint according to its purpose, so the API Gateway

will load all endpoints that point to all existing microservices.

Eduvest – Journal of Universal Studies

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563 http://eduvest.greenvest.co.id

The advantage of using a microservice architecture is the ease of integration on

various application platforms more easily such as website, mobile and desktop applications.

With the use of API, the process of exchanging data becomes easier and faster. From the

client side, this is done by sending a request body and header as needed via an HTTP

request, then the server will respond via an HTTP response. The client creates a UI and

then integrates it with the API Gateway services to get a response from the microservices.

If the application has a need for adding new features, then it is necessary to add new

microservices, so application development becomes easier because there is no need to

completely overhaul the application. In addition to adding services, by using the

microservices architecture, the system will become easier to accept new clients.

Microservices should not be accessed directly by the public, so as not to cause data

leakage. Therefore, an authentication is required for each microservice. Authentication on

microservices needs to be done to secure the services themselves from crimes on the

internet. To overcome and avoid the above problems, an API gateway application was

made.

The function of the API Gateway is to connect the services that have been created

with the client. API Gateway can add several other functions such as logging,

authentication, rate limiting, caching, transforming and load balancing. So that clients can

access the API Gateway application service on the internet indirectly, and only clients who

have been given access can access the API Gateway.

Figure 3 API Gateway Illustratuion

Microservices applications can be accessed via API Gateway. so every client must

fire API Gateway first to be able to access Microservices. Because the API Gateway can

only be accessed by the public, so it needs a security on the API Gateway. For this reason,

API Gateway added Authentication or Authorization features. The author uses Json Web

Token or better known as JWT which is a random token in the form of a string with

functions to authenticate the system and exchange information. The token contains the

information or data required by the user. JWT tokens are usually sent using a url and using

Bernardus Redika Westama Putra and Evangs Mailoa

Implementation Of Microservices In Fintech Applications Using Expressjs Framework

564

the post method or in the header (Rahmatulloh, Sulastri, & Nugroho, 2018) (Edy,

Ferdiansyah, Pramusinto, & Waluyo, 2019).

Figure 4 Examples of Functions in the API

In the application that is made, the JWT formula consists of the payload or request

body,            

needed, as well as the expressin or expiration time of the token. The gateway also requires

a username and password, so every client who wants to access the gateway needs to first

to access the gateway. After the username and password are registered, they can access the

gateway.

Testing using the Postman application. Request body contains username, password,

and tokenexp in JSON format. The request is sent to the server, then the server will give

two types of response, namely a successful response and a failed response. The response is

successful if the username and password are correct and registered in the database.

Response fails if the username has not been registered in the database. The response

received also has a JSON format, each username has a different token. Tokens that have

been successfully generated also have a time limit. If the token has passed the time limit,

then the token cannot be used again and must be generated again.

Figure 5 Data in Json

Figure 6 Tokenization

Eduvest – Journal of Universal Studies

Volume 1 Number 7, July 2021

565 http://eduvest.greenvest.co.id

The next experiment, testing the endpoint that has been created using the token that

was generated earlier. As a result, the server will provide a response containing the required

data.

Example: endpoint account statement

Figure 7 JWT Token Implementation

The last experiment is implementation to several platforms, namely website and

mobile. Making a website using the ReactJs framework and mobile using Flutter, in Figures

1.8 and 1.9 it can be seen that the microservice that has been built can run well.

Figure 8 Implementation on the web

Figure 9 Implementation on mobile

 
 
Bernardus Redika Westama Putra and Evangs Mailoa 
Implementation Of Microservices In Fintech Applications Using Expressjs Framework
    566 
CONCLUSION 
 
Based on the discussion and testing that has been carried out, several conclusions 
can  be  drawn  namely  Microservice  makes  application  development  easier  and  more 
flexible  by  adding  services  as  needed.  Make  it  easier  for  other  applications  to  access 
services that have been made via HTTP Requests, another thing is to facilitate application 
integration between platforms, both mobile, web and desktop. 
  Json web token on api gateway creates application becomes more secure because 
the application cannot be accessed if not using token. Framework ExpressJs is proven to 
be able to well build microservices and supports restful api development. 
  The microservice application system that has been created still has shortcomings 
that  must  be  improved.  The  author's  suggestion  for  further  researchers  is  that  the 
authentication system needs to add certain encryption or other methods to further secure 
important data in the database. 
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