It's really interesting to see which of the new UK and European 'challenger' banks purchased third-party banking software and which decided to spend the time writing their own modern banking systems [1]. A few examples from the linked article...
Monzo: For banking ops, it decided to build its own platform. Technology used is mainly open source: Linux, Apache Cassandra distributed database (used by the likes of Apple and Twitter), Google’s Go (golang) programming language at the back-end and PostgreSQL relational database. The system is hosted at two data centres in the UK on Mondo’s own hardware. There is a team of 16 people working on this.
Atom Bank: It has created a hefty technology set-up in its run up to the launch: FIS’s Profile core banking system; FIS/Sungard’s Ambit Quantum and Ambit Focus for treasury and risk management; Iress’ Mortgage Sales & Origination (MSO) suite for mortgage business, front-to-back office; Wolters Kluwer’s OneSumX for regulatory reporting; Intelligent Environments (IE) for front office capabilities; CSC’s ConfidentID system for security; Phoebus Software for secured business lending and account servicing for residential lending; and WDS Virtual Agent for customer queries supplied by WDS (a subsidiary of Xerox).
Starling: The bank has an in-house developed core system. It uses GPS and Bottomline Technologies for processing and payments operations, respectively.
At what point does it become cheaper to buy one of these smaller banks and migrate everyone across to their platform?
[1] https://www.bankingtech.com/2018/04/uk-challenger-banks-whos...