Hi William, I've been down this path recently. You're right that it's significantly more expensive at around 4p per SMS in the UK. After some research, Twilio seems to be the most competitive on SMS pricing so it's not a case of overcharging. I looked into making WhatsApp the primary communication channel but it's tricky. The official integration ($10/month/per sub account) doesn't sync with your phone and requires templated responses to work. It's not a great replacement to SMS in my opinion. The other way is using a service like WAGHL which is $29/month/per sub account. This will sync with your phone and allow to use WhatsApp normally without templated responses, but you'd need to be sending well over 500 SMS per month per sub account to get any savings at that price. Also, WAGHL isn't an official integration and could be shut down any day. Overall, I came to the conclusion that while SMS in the UK is more expensive, it's still a very manageable monthly expense. Even if you rack up £20 in SMS costs per month per client, you should still be seeing healthy margins if you're charging a reasonable amount.