micro

# Micro — Asynchronous HTTP microservices

## Features

- **Easy**: Designed for usage with `async` and `await`
- **Fast**: Ultra-high performance (even JSON parsing is opt-in)
- **Micro**: The whole project is ~260 lines of code
- **Agile**: Super easy deployment and containerization
- **Simple**: Oriented for single purpose modules (function)
- **Standard**: Just HTTP!
- **Explicit**: No middleware - modules declare all [dependencies](https://github.com/amio/awesome-micro)
- **Lightweight**: With all dependencies, the package weighs less than a megabyte

**Disclaimer:** Micro was created for use within containers and is not intended for use in serverless environments. For those using Vercel, this means that there is no requirement to use Micro in your projects as the benefits it provides are not applicable to the platform. Utility features provided by Micro, such as `json`, are readily available in the form of [Serverless Function helpers](https://vercel.com/docs/runtimes#official-runtimes/node-js/node-js-request-and-response-objects).

## Installation

**Important:** Micro is only meant to be used in production. In development, you should use [micro-dev](https://github.com/vercel/micro-dev), which provides you with a tool belt specifically tailored for developing microservices.

To prepare your microservice for running in the production environment, firstly install `micro`:

```bash
npm install --save micro
```

## Usage

Create an `index.js` file and export a function that accepts the standard [http.IncomingMessage](https://nodejs.org/api/http.html#http_class_http_incomingmessage) and [http.ServerResponse](https://nodejs.org/api/http.html#http_class_http_serverresponse) objects:

```js
module.exports = (req, res) => {
  res.end('Welcome to Micro');
};
```

Micro provides [useful helpers](https://github.com/vercel/micro#body-parsing) but also handles return values – so you can write it even shorter!

```js
module.exports = () => 'Welcome to Micro';
```

Next, ensure that the `main` property inside `package.json` points to your microservice (which is inside `index.js` in this example case) and add a `start` script:

```json
{
  "main": "index.js",
  "scripts": {
    "start": "micro"
  }
}
```

Once all of that is done, the server can be started like this:

```bash
npm start
```

And go to this URL: `http://localhost:3000` - 🎉

### Command line

```
  micro - Asynchronous HTTP microservices

  USAGE

      $ micro --help
      $ micro --version
      $ micro [-l listen_uri [-l ...]] [entry_point.js]

      By default micro will listen on 0.0.0.0:3000 and will look first
      for the "main" property in package.json and subsequently for index.js
      as the default entry_point.

      Specifying a single --listen argument will overwrite the default, not supplement it.

  OPTIONS

      --help                              shows this help message

      -v, --version                       displays the current version of micro

      -l, --listen l