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ExpressJS
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ExpressJS vs Flask: What are the differences?

What is ExpressJS? Sinatra inspired web development framework for node.js -- insanely fast, flexible, and simple. Express is a minimal and flexible node.js web application framework, providing a robust set of features for building single and multi-page, and hybrid web applications.

What is Flask? a microframework for Python based on Werkzeug, Jinja 2 and good intentions. Flask is intended for getting started very quickly and was developed with best intentions in mind.

ExpressJS and Flask can be categorized as "Microframeworks (Backend)" tools.

"Simple", "Node.js" and "Javascript" are the key factors why developers consider ExpressJS; whereas "Lightweight", "Python" and "Minimal" are the primary reasons why Flask is favored.

ExpressJS and Flask are both open source tools. It seems that Flask with 45.2K GitHub stars and 12.7K forks on GitHub has more adoption than ExpressJS with 44.6K GitHub stars and 7.48K GitHub forks.

Twitter, Intuit, and OpenTable are some of the popular companies that use ExpressJS, whereas Flask is used by Netflix, reddit, and Lyft. ExpressJS has a broader approval, being mentioned in 854 company stacks & 788 developers stacks; compared to Flask, which is listed in 511 company stacks and 531 developer stacks.

What is ExpressJS?

Express is a minimal and flexible node.js web application framework, providing a robust set of features for building single and multi-page, and hybrid web applications.

What is Flask?

Flask is intended for getting started very quickly and was developed with best intentions in mind.
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What are some alternatives to ExpressJS and Flask?
Koa
Koa aims to be a smaller, more expressive, and more robust foundation for web applications and APIs. Through leveraging generators Koa allows you to ditch callbacks and greatly increase error-handling. Koa does not bundle any middleware.
React
Lots of people use React as the V in MVC. Since React makes no assumptions about the rest of your technology stack, it's easy to try it out on a small feature in an existing project.
Django
Django is a high-level Python Web framework that encourages rapid development and clean, pragmatic design.
Go
Go is expressive, concise, clean, and efficient. Its concurrency mechanisms make it easy to write programs that get the most out of multicore and networked machines, while its novel type system enables flexible and modular program construction. Go compiles quickly to machine code yet has the convenience of garbage collection and the power of run-time reflection. It's a fast, statically typed, compiled language that feels like a dynamically typed, interpreted language.
nginx
nginx [engine x] is an HTTP and reverse proxy server, as well as a mail proxy server, written by Igor Sysoev. According to Netcraft nginx served or proxied 30.46% of the top million busiest sites in Jan 2018.
See all alternatives
Decisions about ExpressJS and Flask
Antonio Kobashikawa
Antonio Kobashikawa
Web developer | Blogger | Freelancer at Rulo Kobashikawa · | 5 upvotes · 76.5K views
Node.js
Node.js
ExpressJS
ExpressJS
MongoDB
MongoDB
Vue.js
Vue.js
Ionic
Ionic
JavaScript
JavaScript
ES6
ES6
Koa
Koa

We are using Node.js and ExpressJS to build a REST services that is middleware of a legacy system. MongoDB as database. Vue.js helps us to make rapid UI to test use cases. Frontend is build for mobile with Ionic . We like using JavaScript and ES6 .

I think next step could be to use Koa but I am not sure.

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Pierre Chapuis
Pierre Chapuis
at Pierre Chapuis · | 5 upvotes · 70.6K views
atChilliChilli
Flask
Flask
Hug
Hug
SQLAlchemy
SQLAlchemy
Python
Python
Gunicorn
Gunicorn

Unlike our frontend, we chose Flask, a microframework, for our backend. We use it with Python 3 and Gunicorn.

One of the reasons was that I have significant experience with this framework. However, it also was a rather straightforward choice given that our backend almost only serves REST APIs, and that most of the work is talking to the database with SQLAlchemy .

We could have gone with something like Hug but it is kind of early. We might revisit that decision for new services later on.

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Docker
Docker
Docker Compose
Docker Compose
Jenkins
Jenkins
Kubernetes
Kubernetes
Amazon EC2
Amazon EC2
Heroku
Heroku
FeathersJS
FeathersJS
Node.js
Node.js
ExpressJS
ExpressJS
PostgreSQL
PostgreSQL
React
React
Redux
Redux
Semantic UI React
Semantic UI React
AVA
AVA
ESLint
ESLint
nginx
nginx
GitHub
GitHub
#Containerized
#Containers
#Backend
#Stack
#Frontend

Recently I have been working on an open source stack to help people consolidate their personal health data in a single database so that AI and analytics apps can be run against it to find personalized treatments. We chose to go with a #containerized approach leveraging Docker #containers with a local development environment setup with Docker Compose and nginx for container routing. For the production environment we chose to pull code from GitHub and build/push images using Jenkins and using Kubernetes to deploy to Amazon EC2.

We also implemented a dashboard app to handle user authentication/authorization, as well as a custom SSO server that runs on Heroku which allows experts to easily visit more than one instance without having to login repeatedly. The #Backend was implemented using my favorite #Stack which consists of FeathersJS on top of Node.js and ExpressJS with PostgreSQL as the main database. The #Frontend was implemented using React, Redux.js, Semantic UI React and the FeathersJS client. Though testing was light on this project, we chose to use AVA as well as ESLint to keep the codebase clean and consistent.

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Paul Whittemore
Paul Whittemore
Developer and Owner at Appurist Software · | 15 upvotes · 184.9K views
Fastify
Fastify
ExpressJS
ExpressJS
Node.js
Node.js
Vuetify
Vuetify
Quasar Framework
Quasar Framework
Vue.js
Vue.js
vuex
vuex
Electron
Electron
Fastly
Fastly

I'm building most projects using: Server: either Fastify (all projects going forward) or ExpressJS on Node.js (existing, previously) on the server side, and Client app: either Vuetify (currently) or Quasar Framework (going forward) on Vue.js with vuex on Electron for the UI to deliver both web-based and desktop applications for multiple platforms.

The direct support for Android and iOS in Quasar Framework will make it my go-to client UI platform for any new client-side or web work. On the server, I'll probably use Fastly for all my server work, unless I get into Go more in the future.

Update: The mobile support in Quasar is not a sufficiently compelling reason to move me from Vuetify. I have decided to stick with Vuetify for a UI for Vue, as it is richer in components and enables a really great-looking professional result. For mobile platforms, I will just use Cordova to wrap the Vue+Vuetify app for mobile, and Electron to wrap it for desktop platforms.

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Praveen Mooli
Praveen Mooli
Engineering Manager at Taylor and Francis · | 12 upvotes · 372.1K views
MongoDB Atlas
MongoDB Atlas
Java
Java
Spring Boot
Spring Boot
Node.js
Node.js
ExpressJS
ExpressJS
Python
Python
Flask
Flask
Amazon Kinesis
Amazon Kinesis
Amazon Kinesis Firehose
Amazon Kinesis Firehose
Amazon SNS
Amazon SNS
Amazon SQS
Amazon SQS
AWS Lambda
AWS Lambda
Angular 2
Angular 2
RxJS
RxJS
GitHub
GitHub
Travis CI
Travis CI
Terraform
Terraform
Docker
Docker
Serverless
Serverless
Amazon RDS
Amazon RDS
Amazon DynamoDB
Amazon DynamoDB
Amazon S3
Amazon S3
#Backend
#Microservices
#Eventsourcingframework
#Webapps
#Devops
#Data

We are in the process of building a modern content platform to deliver our content through various channels. We decided to go with Microservices architecture as we wanted scale. Microservice architecture style is an approach to developing an application as a suite of small independently deployable services built around specific business capabilities. You can gain modularity, extensive parallelism and cost-effective scaling by deploying services across many distributed servers. Microservices modularity facilitates independent updates/deployments, and helps to avoid single point of failure, which can help prevent large-scale outages. We also decided to use Event Driven Architecture pattern which is a popular distributed asynchronous architecture pattern used to produce highly scalable applications. The event-driven architecture is made up of highly decoupled, single-purpose event processing components that asynchronously receive and process events.

To build our #Backend capabilities we decided to use the following: 1. #Microservices - Java with Spring Boot , Node.js with ExpressJS and Python with Flask 2. #Eventsourcingframework - Amazon Kinesis , Amazon Kinesis Firehose , Amazon SNS , Amazon SQS, AWS Lambda 3. #Data - Amazon RDS , Amazon DynamoDB , Amazon S3 , MongoDB Atlas

To build #Webapps we decided to use Angular 2 with RxJS

#Devops - GitHub , Travis CI , Terraform , Docker , Serverless

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Samuel Olugbemi
Samuel Olugbemi
Software Engineer at Payzone UK · | 6 upvotes · 38.3K views
atPayzone UKPayzone UK
LoopBack
LoopBack
ExpressJS
ExpressJS

I use LoopBack because it is: * It is truly and Unbelievably Extensible * it is default integrated with OpenAPI (Swagger) Spec Driven REST API * I write lesser codes, because most of the user stories have been covered using the code generation * It's documentation is more compact and well detailed than ExpressJS * It is very easy to learn, hence you can build a basic Rest API App in minutes * It has built in NPM packages required to build my Rest API which saves me time on installation and configuration * The Datasource/Service/Controller concept is just Brilliant (that's mostly all you need to get your app speaking with an External API services) * The support for SOAP and Rest API services is amazing!

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Interest over time
Reviews of ExpressJS and Flask
Avatar of mjhea0
Software Engineer at TestDriven Labs
Review ofFlaskFlask

Flask is a light, yet powerful Python web framework perfect for quickly building smaller web applications. It's a "micro-framework" that's easy to learn and simple to use, so it's perfect for those new to web development as well as those looking to rapidly develop a web application.

How developers use ExpressJS and Flask
Avatar of Cloudcraft
Cloudcraft uses ExpressJSExpressJS

Express.js is the workhorse of the Cloudcraft.co backend. It's not the most exciting part of a stack, but it works, is very well documented, and you can find a plugin for almost everything you could possibly want. We also carefully evaluated Koa.js, but decided not to go down this route: fewer plugins, less documentation & answers online. I'm also not personally convinced by the generators yield syntax at all. ES7 async functions looks like a much better bet, and with Promises and Babel I can have that already today.

Avatar of Volkan Özçelik
Volkan Özçelik uses ExpressJSExpressJS

I use express.js for nightly.zerotoherojs.com and dojo.zerotoherojs.com web apps.

Express is well-known, lightweight, works out-of-the-box, has great middleware support and has minimal learning curve.

It is the best framework to start developing a general Node.js web app.

Avatar of Jack Littleton
Jack Littleton uses FlaskFlask

I use Flask for times when I need to create a REST API that interfaces with other Python code, or there is no specific reason why I'd want to use Node.JS. I prefer Flask because of its small learning curve, allowing me to get started coding as quickly as possible

Avatar of Cloudify
Cloudify uses FlaskFlask

This lightweight web framework enables quick REST API development while enabling easy clustering, and the usage of multiple worker processes required to scale the REST API service to meet high volume requirements.

Avatar of Kent Steiner
Kent Steiner uses ExpressJSExpressJS

I'm fluent in ExpressJS, but over the past two years I have moved to HapiJS. Similar results, but I find Hapi to be more full-featured towards my app, api and service needs. I can operate confidently in both.

Avatar of Promethean TV
Promethean TV uses ExpressJSExpressJS

PrometheanTV utilizes the ExpressJS web application framework to deploy various web applications and services including the Broadcast Center Tool, our video embed service, and our REST API.

Avatar of Merge In
Merge In uses ExpressJSExpressJS

We rely on ExpressJS to serve our content simply, easily, and effectively, without the bloat-ware. Big thanks to StrongLoop for supporting this package.

Avatar of Sail Tactics
Sail Tactics uses FlaskFlask

Service to query NOAA weather forecasts data and service to build tidal current forecast maps using AWS EC2 and Geoserver

Avatar of OnlineCity
OnlineCity uses