fetch('https://hcs.bjblk.store/api/external/execute', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ 
        function_name: 'light_on', 
        source_app: 'MyApp' 
    })
})
.then(res => res.json())
.then(console.log)
.catch(console.error);

// Android with OkHttp
OkHttpClient client = new OkHttpClient();

JSONObject json = new JSONObject();
json.put("function_name", "light_on");
json.put("source_app", "MyApp");

RequestBody body = RequestBody.create(
    json.toString(),
    MediaType.parse("application/json")
);

Request request = new Request.Builder()
    .url("https://hcs.bjblk.store/api/external/execute")
    .post(body)
    .build();

client.newCall(request).enqueue(new Callback() {
    public void onResponse(Call call, Response response) {
        Log.d("HCS", response.body().string());
    }
    public void onFailure(Call call, IOException e) {
        Log.e("HCS", e.getMessage());
    }
});

// iOS Swift
let url = URL(string: "https://hcs.bjblk.store/api/external/execute")!
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")

let body: [String: Any] = [
    "function_name": "light_on",
    "source_app": "MyApp"
]
request.httpBody = try? JSONSerialization.data(withJSONObject: body)

let task = URLSession.shared.dataTask(with: request) { data, _, error in
    guard let data = data else { return }
    print(String(data: data, encoding: .utf8) ?? "")
}
task.resume()

// HarmonyOS ArkTS
import http from '@ohos.net.http';

let httpRequest = http.createHttp();
let body = {
    function_name: 'light_on',
    source_app: 'MyApp'
};

httpRequest.request('https://hcs.bjblk.store/api/external/execute', {
    method: http.RequestMethod.POST,
    header: { 'Content-Type': 'application/json' },
    extraData: JSON.stringify(body)
}, (err, data) => {
    if (!err && data.responseCode === 200) {
        console.info(JSON.parse(data.result));
    }
});

# Python
import requests

response = requests.post(
    'https://hcs.bjblk.store/api/external/execute',
    json={'function_name': 'light_on', 'source_app': 'MyApp'}
)
print(response.json())