How to Post JSON Data using cURL in PHP

Updated onbyAlan Morel
How to Post JSON Data using cURL in PHP

JSON is the most popular data format on the web because it is natively supported in JavaScript and human-readable.

As such, many APIs support the ability to send and receive JSON data.

In this tutorial, we will learn how to send JSON data to a URL using cURL in PHP.

Sending JSON Data to a URL

To send JSON data to a URL, first let's define the array we want to send:

PHP
$data = [ 'name' => 'John Doe', 'age' => 30 ];

Now let's encode the array as JSON:

PHP
$json = json_encode($data);

Not that we have our JSON, let's initialize a cURL request:

PHP
$ch = curl_init();

Now let's apply a few options:

PHP
curl_setopt($ch, CURLOPT_URL, 'https://example.com/api'); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_POST, true); curl_setopt($ch, CURLOPT_POSTFIELDS, $json); curl_setopt($ch, CURLOPT_HTTPHEADER, [ 'Content-Type: application/json', 'Content-Length: ' . strlen($json) ]);

Finally, let's execute the request:

PHP
$output = curl_exec($ch);

Now, we can close the cURL request:

PHP
curl_close($ch);

Taken all together, we can write a reusable function for this:

PHP
$data = [ 'name' => 'John Doe', 'age' => 30 ]; function post_json($url, $data) { $json = json_encode($data); $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_POST, true); curl_setopt($ch, CURLOPT_POSTFIELDS, $json); curl_setopt($ch, CURLOPT_HTTPHEADER, [ 'Content-Type: application/json', 'Content-Length: ' . strlen($json) ]); $output = curl_exec($ch); curl_close($ch); return $output; } $output = post_json('https://example.com/api', $data); echo $output;

Conclusion

In this post, we learned how to send JSON data to a URL using cURL in PHP.

Simply initialize a new cURL request, apply a few options, and execute the request with the given url and data.

Thanks for reading!

Then, we can close the cURL request and return the output.

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