Traditionally applications have been built as monoliths; single applications which become larger and more complex over time, which limit our ability to react to change. An example of this is the banking industry where mergers and acquisitions between banks have lead to a patchwork of different systems & technologies that cost billions of dollars per year to maintain. As a result, the pace of innovation in the banking industry has slowed to a crawl. At Mondo we're building a new kind of bank, a smart bank that belongs in the 21st century, and we’re building it almost entirely in Go. This talk will cover how we’re developing new core banking systems from scratch backed by a microservice platform written in Go, running across multiple data centres using open source frameworks and tools including Docker and Mesos. We'll look at why Go is perfectly suited to this, our architectural decisions, common pitfalls to avoid, and how microservice architectures can vastly increase both the velocity of development teams and the scalability and fault tolerance of our systems.