When comparing Express.js vs Koa, the Slant community recommends Express.js for most people. In the question“What are the best backend web frameworks?” Express.js is ranked 3rd while Koa is ranked 33rd. The most important reason people chose Express.js is:
Setting up a new Express project is very easy. It consists of installing a handful of libraries through NPM run a single `npm install` and everything is ready to go.
Ranked in these QuestionsQuestion Ranking
Pro Setting up is very easy
Setting up a new Express project is very easy. It consists of installing a handful of libraries through NPM run a single
npm install and everything is ready to go.
Pro Great routing API
Express' extremely powerful routing API allows developers to do tasks ranging from building a REST API to building the routes for a simple web app and then take it to the next level by using route parameters and query strings.
Pro Great for beginner Node.js programmers
With a little learning curve, it is a good choice for new NodeJS developers to get started quickly. Express boasts great, thorough documentation.
Pro Express.js is in the Node.js Foundation Incubator Program
Pro Relatively mature
Being a somewhat old Node.js web app framework and being one of the most widely used frameworks, Express.js has matured quite a lot during all that time. It's more stable than its competitors and a huge community backing it.
Pro Support for a lot of plugins
Express takes advantage of Node's NPM to distribute and install countless plugins made by third parties which solve almost anything a developer would want to do with Express.
Pro Has the largest userbase
It's by far the most popular framework for node.
Pro Great supportive community
Express has a big community with a lot of guides and tutorials written about it by developers that have been using it for quite some time.
Pro Good Oauth/Facebook integration with connect module
You can easily add oAuth integration/social logins to your next web app without much hassle, using this authentication middleware for connect.
Pro Has detailed information
Very simple and fast.
Pro Massive ecosystem of middleware
If you have not already checked out the Express.js ecosystem of middleware, you should.
Pro Generator support from ground up
Using generators (a bleeding edge feature, even for Node.js) would clean up your code from the mess caused by all those callbacks; making your code more manageable.
Pro Extremely lightweight
Koa is very lightweight with just 550 lines of code.
Pro async/await keywords are supported and has transcended beyond generator functions
Generators functions are of course a huge plus, but at the time Koa team has transcended generations functions and shifted towards async/await style programming. It has made the Koa best framework available in the market.
Pro Development team has a proven track record
Koa is developed by the team behind a widely used node.js framework (express.js).
Pro Built for ES6
Con No single recommended way of doing something
Express considers itself to be a "minimalistic unopinionated framework", it basically lets the developer determine how their project will be organized. On one hand, this gives anyone terrific power and flexibility to use any library they want for a certain task and to organize their project structure however they want. But on the other hand, there's no single recommended way of organizing things, which can be a trap for beginners and experienced developers alike and result in unmaintainable projects.
Con Community is relatively small
Con Not compatible with express style middleware
Koa uses generators which are not compatible with any other type of Node.js framework middleware.