How does Prophet (and decomposable forecasting) work, and when does it beat or lose to ARIMA and gradient boosting?
Prophet treats forecasting as curve-fitting trend plus seasonality plus holidays, rather than as a stochastic process. The signal is knowing why that design wins on business data and where it quietly fails. Here is the answer.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
Prophet treats forecasting as curve-fitting trend plus seasonality plus holidays, rather than as a stochastic process. The signal is knowing why that design wins on business data and where it quietly fails. Here is the answer.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
