I have recently checked Nexmo and Twilio and they both requested fees for the api messages, while when browsing facebook I couldn't find their pricing. Can you please tell me more about facebook services and where can I find the least cost messaging api service provider?
Thank you
WhatsApp pricing can be fairly complicated, as there are the potential for per-message fees as well as setup and monthly costs to just have access to the Business API. It is not like sending an SMS message, and Facebook has some barriers for WhatsApp to be programmatically used.
A basic overview of the WhatsApp portion of the fees can be found at https://developers.facebook.com/docs/whatsapp/pricing/.
I don't want it to sound like a cop-out, but if you are interested in using Nexmo/Vonage as the provider, the best option to to contact our Sales department at https://www.nexmo.com/contact-sales . They can give you a more in-depth answer depending on the volume of messages, what kind of messages you want to send, and more.