An oral history of Bank Python (2021)

Large investment banks use proprietary Python systems called "Bank Python," which are heavily customized forks of the standard Python ecosystem built around custom infrastructure like "Barbara," a global key-value database that stores most of the bank's operational data including trades, instruments, and market information. These systems are largely unknown to the public despite thousands of engineers working within them, and they differ significantly from standard Python in architecture and capabilities. The article uses a fictional example called "Minerva" to explain how these banking systems operate, detailing how they rely on simple but robust data storage solutions rather than traditional filesystems.