I started building Investment Journey Simulator because I kept running into the same problem with long-term investment calculators: most of them assume the journey is almost perfectly smooth.
You invest the same amount every month, choose an expected return, pick a time horizon and get a final number.
Investment Journey Simulator is an open-source Python + Streamlit tool for modelling how real-life decisions change long-term investment outcomes. Simulate SIPs, step-ups, pauses, lump sums, withdrawals, rebalancing, inflation, taxes, historical scenarios and Monte Carlo paths. Compare complete journeys and use Shapley-based attribution to explain which decisions created the difference. It does not predict markets or recommend investments.
