What's the difference between Open Banking and PSD2?

Open Banking and PSD2 are often talked about as one, but they were developed separately and are now happily coming together. Open Banking is a UK initiative aiming to open up the retail banking market whereas PSD2 is EU Legislation. Whilst Open Banking and PSD2 don’t have exactly the same scope or rules, they are coming into line with each other and do open up great new solutions for everyone.