Freckle’s stack is intentionally simple: we have a single Postgres database, a single API service, a suite of background jobs, and a handful of frontend SPAs (one for students, one for teachers, one for staff, etc).Everything is hosted on AWS and managed using Infrastructure as Code through CloudFormation. We have a custom CLI for handling CloudFormation templates, sanding a number of rough edges and adding features such as ChangeSet review on PRs that change infrastructure. That CLI is written in Haskell and I hope to open source its core in the next few weeks.Everything is containerized, and our services are almost exclusively ECS-Fargate, and the frontends are deployed to S3 behind CloudFront.All of our backend services and most of our tooling is written in Haskell. We use Yesod as the web framework in the API service, which also means Persistent (and Esqueleto) as our database library. On the frontend, we use React with Flow for types, but are attempting a TypeScript migration now.