A rich framework for building restful API services. hapi is a configuration-centric framework in which authentication requirements, input validation, data caching and pre-fetching, developer documentation, and other essential facilities are provided out-of-the-box and enabled using simple JSON configuration objects. hapi enables developers to focus on writing reusable business logic instead of spending time with everything else.

Current version: 0.13.0

Getting started

To demonstrate a basic example we will be creating a "hello world" service with a single API endpoint.

Hello World Server

Start by creating a package.json by running

npm init

Now install hapi and have it saved to your package.json dependencies by running

npm install hapi --save

Next create an index.js file and add the following contents to it:

var Hapi = require('hapi');

// Create a server with a host and port
var server = new Hapi.Server('localhost', 8000);

// Define the route
var hello = {
    handler: function (request) {
    
        request.reply({ greeting: 'hello world' });
    }
};

// Add the route
server.route({
    method: 'GET',
    path: '/hello',
    config: hello
});

// Start the server
server.start();

Start the server with node . and navigate to the website at 'http://localhost:8000/hello' in a browser and you will see the following output:

{"greeting":"hello world"}

Hello World Server + Validation

To demonstrate one of the more powerful features in hapi we will change the 'hello' route to only respond whenever a 'name' is present on the querystring. Change the 'index.js' so that the 'hello' config object looks like the following:

var hello = {
    handler: function (request) {
    
        request.reply({ greeting: 'hello ' + request.query.name });
    },
    validate: { 
        query: {
            name: Hapi.Types.String().required()
        }
    }
};

When you start the server with node . and navigate to 'http://localhost:8000/hello' you will get a 400 response with an error explaining that 'name' is required. When the 'name' is omitted from the querystring the handler will not be called. However, if you do provide a 'name' it will be echoed out in the response. If you request 'http://localhost:8000/hello?name=John' then you will get the following response:

{"greeting":"hello John"}

To learn more about the various validation options you can read the validation section in the reference.

API Reference