An automatic forecasting system developed by Facebook. Use this tag for any on-topic question that (a) involves Prophet either as a critical part of the question or expected answer and (b) is not just about how to use Prophet.
Prophet is an open-source forecasting method that models trend, seasonality and holiday effects. It is available for both R any Python. The pertinent article is Taylor & Letham (2018), "Forecasting at Scale", The American Statistician, 72, 37-45.