What is 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.
Koa is a tool in the Microframeworks (Backend) category of a tech stack.
Koa is an open source tool with 27.1K GitHub stars and 2.5K GitHub forks. Here’s a link to Koa's open source repository on GitHub

Who uses Koa?

57 companies reportedly use Koa in their tech stacks, including Dial Once, Hostr, and Pubu.

171 developers on StackShare have stated that they use Koa.

Why developers like Koa?

Here’s a list of reasons why companies and developers use Koa
Top Reasons
Koa Reviews

Here are some stack decisions, common use cases and reviews by companies and developers who chose Koa in their tech stack.

Lee Benson
Lee Benson
React Router
Semantic UI
React Helmet

ReactQL is a React + GraphQL front-end starter kit. #JSX is a natural way to think about building UI, and it renders to pure #HTML in the browser and on the server, making it trivial to build server-rendered Single Page Apps. GraphQL via Apollo was chosen for the data layer; #GraphQL makes it simple to request just the data your app needs, and #Apollo takes care of communicating with your API (written in any language; doesn't have to be JavaScript!), caching, and rendering to #React.

ReactQL is written in TypeScript to provide full types/Intellisense, and pick up hard-to-diagnose goofs that might later show up at runtime. React makes heavy use of Webpack 4 to handle transforming your code to an optimised client-side bundle, and in throws back just enough code needed for the initial render, while seamlessly handling import statements asynchronously as needed, making the payload your user downloads ultimately much smaller than trying to do it by hand.

React Helmet was chosen to handle <head> content, because it works universally, making it easy to throw back the correct <title> and other tags on the initial render, as well as inject new tags for subsequent client-side views.

styled-components, Sass, Less and PostCSS were added to give developers a choice of whether to build styles purely in React / JavaScript, or whether to defer to a #css #preprocessor. This is especially useful for interop with UI frameworks like Bootstrap, Semantic UI, Foundation, etc - ReactQL lets you mix and match #css and renders to both a static .css file during bundling as well as generates per-page <style> tags when using #StyledComponents.

React Router handles routing, because it works both on the server and in the client. ReactQL customises it further by capturing non-200 responses on the server, redirecting or throwing back custom 404 pages as needed.

Koa is the web server that handles all incoming HTTP requests, because it's fast (TTFB < 5ms, even after fully rendering React), and its natively #async, making it easy to async/await inside routes and middleware.

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Antonio Kobashikawa
Antonio Kobashikawa
Web developer | Blogger | Freelancer at Rulo Kobashikawa · | 4 upvotes · 29.1K views

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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Dave Woolfenden
Dave Woolfenden
Senior Enterprise Architect at eVectis Technologies LLC · | 1 upvotes · 2K views

As a smaller, more expressive, and more robust foundation for web applications and APIs. Koa

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Paul Whittemore
Paul Whittemore
Owner and Developer at Appurist Software · | 1 upvotes · 1.8K views

Will base most server-side APIs on Fastify . Smaller, faster, easier. Faster than Koa; and twice as fast as ExpressJS.

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Koa's Features

  • Provides 3 different kinds of functions as middleware
  • common function
  • async function
  • generator function

Koa Alternatives & Comparisons

What are some alternatives to Koa?
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.
Flask is intended for getting started very quickly and was developed with best intentions in mind.
Django REST framework
Django REST framework is a powerful and flexible toolkit that makes it easy to build Web APIs.
Sinatra is a DSL for quickly creating web applications in Ruby with minimal effort.
hapi is a simple to use configuration-centric framework with built-in support for input validation, caching, authentication, and other essential facilities for building web applications and services.
See all alternatives

Koa's Stats

Koa's Followers
173 developers follow Koa to keep up with related blogs and decisions.
chunrong liu
Arun Kumar
Anand Pathak
Mohamad Naji
Andre  Luiz
Mathieu Kim RObin
Soros Liu