Capital One created an API for its hackathon called Nessie which gives programmers access "to a multitude of real public-facing data - such as ATM and bank branch locations - along with mock customer account data." Participants can use "HTTP requests to set up peer-to-peer transactions, simulate a weekly paycheck, or even schedule bills for customers." This is all structured in a way that resembles how things are run at Capital One.
Hackathon participants can access the data through the Nessie API, which is accessible through GitHub.
The purpose of the hackathons is to encourage co-creation and developer engagement in order to build better customer experiences and address economic challenges with Capital One's APIs.