How to add WhatsApp to your SaaS
To add WhatsApp to a SaaS, you connect each customer's own number to Meta's official Cloud API, receive their messages on a webhook and send replies through a REST API. With a gateway such as Nodium this takes five steps and no Meta app of your own.
The five steps
- Create an account and an API key. The key (
nod_…) drives your whole account. - Add each customer as a client (
POST /tenants), with your own identifier. See one key for all your customers. - Send them a connect link. They connect their own number through Meta's signup, in a few minutes. See the connect link.
- Register one webhook. Every message your customers' contacts send arrives as
message.received, signed. - Send. A template to write first, free text to reply within 24 hours.
# 1. Write first to a customer: on WhatsApp, an approved templatecurl https://nodium.io/api/v1/messages \ -H "Authorization: Bearer $NODIUM_KEY" \ -H "Content-Type: application/json" \ -d '{ "channelId": "<channel id>", "to": "+33612345678", "type": "template", "templateName": "order_ready", "templateLanguage": "en", "variables": { "1": "Karim" }, "idempotencyKey": "order-1042-confirmation" }'# 2. The customer answers: you receive message.received on your webhook.# Reply in free text, within 24 hours:curl https://nodium.io/api/v1/messages \ -H "Authorization: Bearer $NODIUM_KEY" \ -H "Content-Type: application/json" \ -d '{ "channelId": "<channel id>", "to": "+33612345678", "type": "text", "text": "Yes, it is ready.", "idempotencyKey": "order-1042-reply-1" }'What WhatsApp imposes, whatever the provider
- The 24-hour window: free text only within 24 hours of the customer's last message; an approved template otherwise.
- Templates are reviewed by Meta before they can be sent.
- Meta bills its own message fees to the WhatsApp Business account of each number. See Meta's pricing explained.
- A number is on the API or on regular WhatsApp, never both; the WhatsApp Business app can stay, with coexistence.
Build it yourself, or use a gateway
Calling Meta directly means creating a Meta app, verifying your business, passing app review and becoming a Tech Provider before a single customer can connect, then maintaining tokens, webhooks and Embedded Signup. A gateway holds all of that. See Tech Provider or Solution Partner.
Frequently asked questions
How long does it take to add WhatsApp to a SaaS?
With a gateway, a first message sent and answered takes an afternoon: an API key, one webhook route and two calls. Connecting each customer then takes them a few minutes, on a hosted page.
Whose number is it?
Your customer's. They connect a number they own, it stays in their WhatsApp Business account, and they can leave with it.