Python

import requests

class Gowa:
    def __init__(self, base_url, user, password, device_id):
        self.base = base_url.rstrip("/")
        self.s = requests.Session()
        self.s.auth = (user, password)
        self.s.headers["X-Device-Id"] = device_id

    def _handle(self, r):
        data = r.json()
        if not r.ok:
            raise RuntimeError(f"{r.status_code} {data.get('code')}: {data.get('message')}")
        return data.get("results")

    def send_text(self, phone, message, **extra):
        return self._handle(self.s.post(f"{self.base}/send/message",
                                        json={"phone": phone, "message": message, **extra}, timeout=60))

    def send_image(self, phone, path, caption=""):
        with open(path, "rb") as f:
            return self._handle(self.s.post(f"{self.base}/send/image",
                                            data={"phone": phone, "caption": caption},
                                            files={"image": f}, timeout=120))

    def chats(self, limit=20):
        return self._handle(self.s.get(f"{self.base}/chats", params={"limit": limit}, timeout=30))


wa = Gowa("http://localhost:3000", "admin", "changeme", "my-device")
print(wa.send_text("628123456789", "Hello from Python"))

import hashlib, hmac
from flask import Flask, request, abort

app = Flask(__name__)
SECRET = b"change-me"

@app.post("/wa-hook")
def hook():
    expected = "sha256=" + hmac.new(SECRET, request.get_data(), hashlib.sha256).hexdigest()
    if not hmac.compare_digest(expected, request.headers.get("X-Hub-Signature-256", "")):
        abort(401)
    event = request.get_json()
    print(event["event"], event.get("payload", {}).get("body"))
    return "", 200