...until Meta decides they want to offer this kind of thing themselves and ban everyone else. Building your SaaS on top of someone else's SaaS is always a gamble, especially if said product is directly sold to users already and not a pure b2b intermediate.
Since recently Meta offers this as per European Union mandate (Digital Markets Act, DMA). For both Whatsapp and Facebook messaging. [0]
Now there are a lot of implementation requirements, basically forcing you to have some kind of messaging provider. Therefore difficult to apply for an open source solution. However there is such an interface.
[0] https://developers.facebook.com/m/messaging-interoperability...
They're already outright banning many OpenClaw usecases via their official API: https://techcrunch.com/2025/10/18/whatssapp-changes-its-term...