Building the CRM was the easy 80%. The last 20%, actually making WhatsApp behave, is where I lost weeks. Sharing the specific landmines because every one of them cost me real debugging time, and if you're building anything on the WhatsApp Business API you will hit these. "Sent" is a lie. Meta's API happily returns sent and then fails to deliver the message. sent is not proof of anything. Only a delivered/read webhook means it actually landed. I built delivery-gated logic on sent e...