Altova DiffDog vs driftcurve

Altova DiffDog has no write-up on Specifiction yet; its figures are above.

driftcurve is an open-source household retirement planning engine for projecting finances and comparing retirement outcomes. It can model multiple household members, account types, debts, mortgages, pensions, Social Security and property sales. Its default Monte Carlo simulations resample annual market data from 1966–2024 across equities, Treasuries, residential real estate, inflation and Bitcoin. Users can adjust historical returns toward their own long-run targets or enter static annual assumptions. Risk-based spending guardrails solve for monthly spending and suggest adjustments based on portfolio thresholds and probability of success. A Compare page puts two scenarios on one chart. In default local mode, household data and saved scenarios stay in browser localStorage, while forecasts run through a Python backend; there is no account or server-side database persistence. Optional multi-user mode adds email/password accounts, server-side sessions, and stored profiles and scenarios. The project offers forecast and guardrails API endpoints, plus authentication, profile and scenario endpoints in multi-user mode. It is free under Apache License 2.0. The maker describes it as an educational modeling tool, not licensed financial, investment, tax or legal advice.