Here’s a good overview of the various banks & fintechs who have built open(ish) APIs, most of whom aren’t Monzo competitors (yet) -
http://11fs.co.uk/blog/banks-doing-apis-better-than-you/
it would be great to see some examples of what’s being built with these APIs, particularly if you’d like to see similar integration’s by developers using Monzo’s API.
Monzo gets a notable mention, as it’s API isn’t fully developed yet.