Loyalty programme recommendations

We've implemented most of the solutions you mention in your post. In term of at scale loyalty programmes, Talon One and Eagle Eye are very strong contenders in this space for real time, API event driven loyalty programmes.

I would say Talon One is more focused on real time allocation and redemption at scale, mostly via API interface and more limited in terms of their own solutions team to support implementation. That is where a partner may come in (like Composed Digital).

Eagle Eye is similar in that it is really built for massive scale, a little more customisable we have found than Talon and they do have a bigger solutions team to support your build from their own internal staff.

Antavo, we had a great experience with them in terms of the solution having a strong UI for users to interact with in creating/supporting the loyalty platform. The Braze integration was really easy, we configured attributes, events and Antavo solutions team made this fairly seamless to work with. They overall had a few more pre-built/canned loyalty events e.g. birthday reminders, point balance is X then send Y type of campaigns.

I'd encourage you to get a Braze focused demo from all your shortlisted vendors then take it from there!