Express.js Mobile App Development: Pros and Cons for Developers


Business owners and numerous entrepreneurs keep experiencing benefits of digital technologies implemented for their needs. Every day, hundreds of new mobile applications come out to compete for the place in the sun. A growing demand for software products triggers the growth of developers’ forge. Today, a mobile app engineer is not limited to a couple of tools for the work. On the contrary, an abundance of instruments to build software for portable devices creates the problem of choice. The principal character of the present article is a framework for a cross-platform JS runtime environment Node.js. Otherwise speaking, it is an outfit of useful features, plugins, and packages to reveal the Node functionality. So, meet Express.js – the representative of the letter E of the MEAN stack.

What is ExpressJS: New Opportunities for Business

It is not a secret that one of the most popular frontend technologies, JavaScript, has an unlimited scope of use. In other words, building an entire website using JS is not a problem. To this effect, ExpressJS performance can be revealed in full breath. Thus, the backend functionality of JS is implemented via the combination of NodeJS and Express.JS development. The first framework is engaged in building server-side apps, while the second one publishes them as websites.

Put in short, you need Express to layer fundamental structure and features required to build a website since NodeJS does not stipulate such capability. The framework is rather lightweight and offers a variety of choices for your templating language.

Perhaps, such introduction of ExpressJS app development can be a bit obscure to the readers who are not engaged in deeps of app building process. So, let’s shape it another way.

  • If your company does not lack the NodeJS engineers, it is not necessary to seek for additional specialists. The existing stuff of your company can get in ExpressJS to learn a robust set of peculiarities offered for making miscellaneous apps.
  • One set of engineers can handle both front- and back-end stages of a project.
  • Engineers are released from the necessity to repeat same code repeatedly. NodeJS uses an HTTP module that stipulates a lot of additional manipulations like parsing the payload, storing sessions etc. Express foresees a simple app development. Hence, a plenty of resources and efforts will be saved.
  • The economic benefit is irrevocable since the working cycle is shorter; the staff doesn’t demand fresh blood, and the cross-platform capability is available.
  • Do you need a single-page app for mobile devices or a multi-page product for the web? You can easily intermix your goals since ExpressJS app development foresees any of the said demands.
  • Complex applications are also available to build quickly with the said framework.

How It Works

The server stipulating an event-driven principle is the core element of interworking between ExpressJS and NodeJS. It is characterized by the lack of the data blockage during processing any received request. Such operation is achieved due to the parallel processing of data to avoid delaying the data flow. Therefore, a bigger number of requests can be processed by NodeJS in a more efficient way.

Another element to be mentioned is MongoDB. Due to JS orientation, this built-in driver does not waste time on the adjustment of the transmitted data to the framework. Once again, no blockage of the flow is foreseen since all requests are processed simultaneously. Even if servers containing the database are located in different remote places, no time delay will be observed due to the described operational scheme.

Benefits of Express JS

If you still hesitate whether ExpressJS mobile app development is the proper option for your business, give a glance at the following benefits:

  1. If you use NodeJS for producing apps, this process can be accelerated and improved with Express.
  2. This framework is simple to customize and configure for certain demands.
  3. Based on URL and HTTP methods, it is possible to define routes of the existing app.
  4. ExpressJS developers can appreciate versatile middleware modules for performing additional tasks on response and request.
  5. Integration with miscellaneous template engines including EJS, Vash, Jade and others is available.
  6. You can define an error processing middleware.
  7. Resources and static files of your app are easy to serve.
  8. Creation of REST API server is one of the most attractive features of app development on ExpressJS.
  9. You can take advantage of connection with such databases as MySQL, Redis, and the abovementioned MongoDB.

Performance of Express JS

One can hear a plenty of praiseful claims about incredible features and usable solutions provided by a certain tool. Still, the most vital thing is its performance. The number of requests processed per second is the most appropriate metric to define productivity within the framework. Since the millisecond delay time is less important than an absolute throughput performance, the metric is true for many web apps.

You can find numerous tests made on versatile systems and upon certain terms. As a rule, such tests foresee a comparison of different frameworks like Restify and Koa in versatile environments.

However, results of a certain test cannot be taken as a benchmark of the framework’s performance as a whole. The number of requests made within a second varies according to the type of tested operations. Still, they show the base metrics.

According to the official review of Express JS, one can optimize its performance by several tricks in both the code and environment. These include the usage of gzip compression, load balancer, reverse proxy, run of the app in a cluster etc. According to DZone, the framework was compared with other tools in 2015, 2016, and 2017. It always showed decent results like 2875 requests per second on Ubuntu VM in 2017. Nevertheless, its competitors Restify, Total, and Koa2 showed higher results.

Comparing To Other Node JS Frameworks and Competitors

Since we brought up a topic of the collation of Express JS for Mobile App Development with other frameworks, let’s see how the principal character of the present article proves itself against Stormpath and Bootstrap.

In fact, it is not absolutely correct to contrapose the mentioned tools. Otherwise speaking, instead of “versus” in ExpressJS vs Stormpath or ExpressJS vs Bootstrap, one should place a plus mark.

Bootstrap is an open source suite of tools with HTML, CSS, and JS. Unlike our principal character, it deals with front-end building only. Stormpath, in turn, is an open user management REST-based application programming interface. This API makes a lot of sense when a project stipulates building a cloud application. With Stormpath one can store data about users, send password reset messages, authorize users, issue keys for API-based web apps and perform a plenty of other useful functions.

Considering the above, making any kind of comparison is pointless since all these three technologies are better to deploy together.

When we talk about competitors represented by other NodeJS frameworks, it should be stated that Express holds leading positions on popularity among computer engineers. Other Sinatra-like frameworks including Locomotive, Hapi, Flatiron, Total.js and others lag behind the leader. Still, Koa and Hapi are more adaptive and adequate for building from the scratch. Derby, Mojito, and Meteor are less flexible and provide standard architecture and technology stack. The already mentioned API Stormpath can face its rivals acting by specialized NodeJS API frameworks such as Restify and LoopBack.

Put in short, the choice of the framework depends on your needs or other personal preferences.

Advantages & Disadvantages for Developers

Computer engineers opt for Express.JS development according to its adjustability, extensibility, high productivity rate, and plainness. The tool is very fast, simple-to-install, and offers an opportunity to extend its features by using various levels of middleware. Another advantage includes routing that simplifies the testing procedure and improves the productivity.

ExpressJS App Development stipulates using one language for both sides of app building process. Therefore, JS engineers are the only service projectile for the project. This leads to the acceleration of the building process and reduction of expenses since one specialist can cope with both building layers namely data access and presentation.

If you search for a minimalist framework, Express should be your choice. Still, to solve different development issues, various middleware packages have been built. These include security headers, URL parameters, libraries, POST data and others.

The notion of opinionated does not refer to ExpressJS. I. e., particular tasks are not subject to strict and fixed regulations. The same refers to the selected components. One can use any middleware in the most suitable order. Besides, the structure of the future app is not also predetermined.

Each coin has two sides. The reverse side of Express.JS development is not free of subtle flaws that can affect the operational cycle.
Computer engineers who are proficient in other software languages may consider the event-driven nature of NodeJS a bit complicated to comprehend. Thus, the scenario of callback hell is possible when a developer misunderstands the nature and writes all the code in callbacks. Still, such possible problems with callbacks are less likely with the last version of the framework.

To get in ExpressJS Mobile App Development, one has to get in the concept of middleware. It represents a subset of coupled functions running among client requests and server responses. Understanding this philosophy is vital to make a go.

Most other disadvantages associated with the framework are more of a subjective nature. Some developers dislike the minimalism inherent to Express, others complain about the freedom of action instead of a standard design pattern etc. Despite all these flaws, the effectiveness of the framework is out of the question.

Advantages & Disadvantages for Clients

The above-mentioned pros & cons are essential to demonstrate technical aspects of working with Express. However, developers and people who want to invest some money in a certain project have different views on the technology. Thus, customers need to see the economic feasibility of the framework to opt for it for the project.

Involving an ExpressJS development company to create large projects is not an appropriate solution. The tool belongs to the cohort of middleware frameworks that are suitable for small and medium projects. It is better to see through a usage example. The framework was chosen by MySpace, PayPal, and Klout to build websites.

Another peculiarity of ExpressJS mobile app development can be deemed both advantage and flaw depending on your existing development team. If your engineers are good in JS, you hit the jackpot. Utilization of one language for front and back-end stages provides a full-stack operation of your developers without additional twists and turns. Obviously, learning some features of the very framework will take some time. Yet, it is a subtle value compared to the time you would spend on searching and recruiting new teammates.

What Can & Can’t Be Built With ExpressJS

In the beginning of the present ExpressJS review, it was stated that the tool is suitable for building apps for both the web and portable devices. These notions are rather generalized and people hesitating what framework to select need a more profound introduction to what can and can’t be created with the said tool.

Apps interworking with external resources

Server-side apps that collect data from third-party resources are a decent implementation of the framework.

Apps to track website visits

If your target is to create the app to receive information about your company on an ongoing basis, as well as to monitor and analyze versatile data, Express.js should be your choice. The tool is a fit to build back-end of apps that track visitors of websites and visualize the data out.

Real-time apps

Another reason to opt for the said framework is the need in the real-time update function of apps. The plain structure and versatility of Express combined with its event-driven nature are perfect for projects that foresee an instant data update like voting results or progress of sports events.

Along with numerous other opportunities of using ExpressJS, this framework is absolutely not recommended for creating heave CPU applications. Long-running CPU tasks will block the whole server because the code, unlike I/O operations, is not executed in parallel. The problem can be solved by launching multiple Node/Express processes running in parallel. Still, such approach will complicate the structure and, frankly, is not a good idea. In addition, the basic framework of ExpressJS is not a friendly environment for mission-critical code and computation-intensive tasks.

Cost to Develop and to Support/Extend Express.Js App

“How much is the fish” is an obligatory question for any client. Unlike building a house or manufacturing a vehicle, web app development requires no additional resources except for personnel. It is a decisive factor in pricing.

Thus, one working hour of an ExpressJS developer from the US costs $20 and more depending on experience and skills. The highest rate found on PeoplePerHour is $80.

If the location of the future engineer is not important for a client, a skillful Express Mobile App Development specialist from Ukraine is cheaper by $5. At the same time, some developers from this European country esteem their experience higher.

The price of ExpressJS development is approximately similar comparing to other JavaScript frameworks including AngularJS, ReactJS, and MeteorJS.

Expected Performance Boost

To define this value, we need to contradistinguish two or more alternatives under consideration for a certain project. If you hesitate between the plain NodeJS and ExpressJS, the latter is the undisputed winner. The lack of deploying different languages and frameworks for both sides of web app development is an unconditional advantage. Otherwise speaking, the working process can be significantly accelerated and simplified.

As a result, a client will have a significant feasibility in case of the existent team of JS developers. If your project requires hiring personnel, you will be released from searching diversified specialists but focus on decent JS engineers. According to the practice of some projects, the cycle of development simple mobile app was cut twofold using ExpressJS. Obviously, such result seems a bit fantastic but it is achievable.

If you are concerned about a learning curve, you should not. Developers that are somehow familiar with JS won’t find troubles to learn NodeJS. Naturally, those who possess skills in web programming using PHP or Python will have a solid understanding of some concepts despite the radical difference of the NodeJS model. Be prepared to a steep learning curve.

Examples of Apps on Express.JS

The final product is a good pro or con argument. The following list of examples and open-source Express.js projects will help you make the final step to your verdict.


It is not an app but a web app framework built using Express.js and MongoDB. Keystone provides database fields, email sending, session management, auto-generated admin user interface, dynamic templates and views, and other miscellaneous features to create database-driven apps and websites.


In the production of this application, Express.js and MongoDB were also used but for building the server side. The frontend side was created with Backbone, Twitter Bootstrap, and RequireJS. ClientManager represents a CRUD application to manage contacts.


A set of publishing tools, optimized distribution channels, and simple content management system is available in the open-source professional publishing platform called Ghost. The number of downloads exceeded 1,200,000 by developers from versatile places around the globe.

Screenshot app

Express showed its benefits in another web service. The idea of the app is disclosed in its name, i.e. making screenshots.


Another NodeJS content management system built with Express, Connect and Mongoose bears the name of Calipso. This project is rather longstanding extending back over more than six years.

Reviews of ExpressJS from Developers

Perhaps, the best way to comprehend the essence of the framework is to listen to the opinion of engineers who have the experience of working with it. In most cases, such epithets as “flexible, minimal API-building NodeJS tool”, “well-structured and easy to learn framework” and “it saved a lot of time on the request parsing and setting up Node environment” can be read from numerous reviews made by developers. Easy-to-learn and freedom of actions are considered the most attractive features of ExpressJS. The framework is highly recommended to use as the tool for a time-constrained project.