My existing project already calls the WhatsApp Cloud API, yet the integration fails somewhere between authentication, message flow, and error handling. I need the entire connection reviewed, debugged, and brought to a point where messages consistently travel both ways without unexpected errors. You’ll start by analysing the current configuration in Meta-developer settings, the webhook setup, and the code that hits the Graph endpoints. Once the root cause is clear, update the code, regenerate any access tokens if necessary, and document the exact steps so I can reproduce the setup on a fresh environment. Deliverables • Corrected, working integration that reliably sends and receives messages through the WhatsApp Cloud API • Clean, commented code or patch notes highlighting every change made • A short, step-by-step guide that covers environment variables, webhook verification, token refresh, and basic testing through Postman or curl When the final test message appears in my WhatsApp inbox and outbound messages show up in the Meta dashboard without errors, the job is done.