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FLAVIO COPES
flaviocopes.com
2026

Send a JSON response using Express

By Flavio Copes

Learn how to send a JSON response in Express using the Response.json() method, which takes an object or array and converts it to JSON before sending it.

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When you listen for connections on a route in Express, the callback function will be invoked on every network call with a Request object instance and a Response object instance.

Example:

app.get('/', (req, res) => res.send('Hello World!'))

Here we used the Response.send() method, which accepts any string.

You can send JSON to the client by using Response.json(), a useful method.

It accepts an object or array, and converts it to JSON before sending it:

res.json({ username: 'Flavio' })
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