We run a large deployment of services to support millions of daily active users across the 450+ cities that the Citymapper app operates in - all on AWS EKS.
Most of the code of the backend services is written in Python and we have CPP and some Go services or modules as we deal with a lot of CPU and memory intensive workloads (eg routing) as well as high I/O workloads (we are using 1000s of different data sources)
The apps and SDK are written in Kotlin / Swift / React
We run a large deployment of services to support millions of daily active users across the 450+ cities that the Citymapper app operates in - all on AWS EKS. Most of the code of the backend services is written in Python and we have CPP and some Go services or modules as we deal with a lot of CPU and memory intensive workloads (eg routing) as well as high I/O workloads (we are using 1000s of different data sources)
The apps and SDK are written in Kotlin / Swift / React