Let's perform the following steps to create an API status endpoint for our Express application:

1. First, let's create a new route for all our API requests. Create a new file called /routes/api.js; inside this file, we will define two new routes:

var express = require('express');
var router = express.Router();

router.get('/', function(req, res, next) {
 res.send('API is running');
});

router.get('/:param', function(req, res, next) {
 var params = req.params;
 var query = req.query;
 Object.assign(params, query);
 res.json(params);
});

module.exports = router;

2. Next, we will update our /app.js configuration to import this new route, and provide it to Express as middleware using the use command:

...
var api = require('./routes/api');
var app = express();

...
app.use(express.static(path.join(__dirname, 'public')));
app.use('/api', api);
...

3. Finally, we must restart our Express server. Now, when we visit localhost:3000/api, we will see the API is running text; if we visit localhost:3000/api/foobar?search=barfoo, we will see a JSON response:

{
  "param":"foobar",
  "search":"barfoo"
}