$curl = curl_init();
curl_setopt_array($curl, [
    CURLOPT_URL => '/cities/:pincode',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_FOLLOWLOCATION => true,
    CURLOPT_ENCODING => "",
    CURLOPT_MAXREDIRS => 10,
    CURLOPT_TIMEOUT => 30,
    CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
    CURLOPT_CUSTOMREQUEST => "GET",
    CURLOPT_HTTPHEADER => ['X-API-KEY' => 'your-api-key'],
]);
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if ($err) {
    return "cURL Error #:" . $err;
} else {
    $data = json_decode($response);
}

const axios = require("axios");
const options = {
    method: 'GET',
    url: '/cities/:pincode',
    headers: {
        'X-API-KEY': 'your-api-key'
    },
};

axios.request(options).then(function (response) {
    console.log(response.data);
}).catch(function (error) {
    console.error(error);
});

var client = new HttpClient();
var request = new HttpRequestMessage
{
    Method = HttpMethod.Get,
    RequestUri = new Uri("/cities/:pincode"),
    Headers =
    {
        { "X-API-KEY", "your-api-key" }
    },
};
using (var response = await client.SendAsync(request))
{
    response.EnsureSuccessStatusCode();
    var body = await response.Content.ReadAsStringAsync();
    Console.WriteLine(body);
}

OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
    .url("/cities/:pincode")
    .addHeader("X-API-KEY", "your-api-key")
    .build();

Response response = client.newCall(request).execute();