Most US federal and state taxes can be computed by a rules engine. The big annual challenges are: updating the interviews, QA-ing the rules/engine, fed/state rule-making delays/defects, and ensuring that required printable forms are pixel-perfect replicas of their government-published sources.
For tax year 2017 (a pretty typical year), there were over 5000 Federal/state forms/interview scripts to be updated. This requires a seasonal army of tax accountant/developers to update the app "content." It's not uncommon for providers to be updating forms/interviews well into March (when filing opens in January).
For tax year 2017 (a pretty typical year), there were over 5000 Federal/state forms/interview scripts to be updated. This requires a seasonal army of tax accountant/developers to update the app "content." It's not uncommon for providers to be updating forms/interviews well into March (when filing opens in January).
Source: worked for a Turbotax competitor