This is an (already built) forecasting tool, which connects with a third party API to pull stock data in. 
The user can then run reports from this data with some key manipulations.
The report is displayed through a frontend (built on React) where the user can manipulate and consume the data within a spreadsheet style widget and re-run the reports.
There’s a fair amount of domain knowledge needed to get up to speed, but this can be shared through documentation.
The backend is built using Ruby-on-Rails, and a React frontend. 
These apps are hosted on Heroku with generated data being stored in S3