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A lean, modular web server for rapid full-stack development.

Lws is an application core for quickly launching a local web server. Behaviour is added via plugins giving you full control over how requests are processed and responses created.

  • Supports HTTP, HTTPS and HTTP2.
  • Small and 100% personalisable. Load and use only the behaviour required by your project.
  • Attach a custom view to personalise how activity is visualised.
  • Programmatic and command-line APIs.


Core usage

Launch an HTTP server on the default port of 8000.

$ lws
Listening at http://mba4.local:8000,,

For HTTPS or HTTP2, pass the --https or --http2 flags respectively.

$ lws --http2
Listening at https://mba4.local:8000,,

Now your server is running, the next step is to attach some middleware to process requests.

Using middleware plugins

Install and use some middleware (lws-static and lws-index) to serve static files and directory listings.

$ npm install --save-dev lws-static lws-index

$ lws --stack lws-static lws-index
Listening at http://mba4.local:8000,,

The current directory will now be available to explore at

Install and use logging middleware. Note the lws- prefix is optional when supplying module names to --stack.

$ npm install --save-dev lws-log

$ lws --stack log static index --log.format combined
Listening at http://mba4.local:8000,,
::ffff: - GET /lws.config.js HTTP/1.1 200 52 - 8.259 ms
::ffff: - GET /package.json HTTP/1.1 200 399 - 1.478 ms

Creating a custom middleware plugin

Lws uses Koa as its middleware engine. Here is a trivial plugin example, save the following code as example-middleware.js:

class ExamplePlugin {
  middleware () {
    return async (ctx, next) => {
      ctx.body = 'Hello from lws!'
      await next()

export default ExamplePlugin

Now launch an HTTP server using this middleware.

$ lws --stack example-middleware.js
Listening at http://mba4.local:8000,,

$ curl
Hello from lws!


$ npm install --save-dev lws


See also

© 2016-22 Lloyd Brookes <75pound@gmail.com>.

Tested by test-runner. Documented by jsdoc-to-markdown.

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