Sindri

Compound interest calculator. Projects the ending value of an investment given a starting principal, monthly contributions, and an annual interest rate, compounded monthly over a chosen number of years.

Cash-on-cash return calculator for real estate investing. Runs a full multi-year deal analysis (per-category rent/expense growth, a sale scenario, IRR) and headlines the first-year cash-on-cash return: operating cash flow divided by invested cash.

Alcohol spending and opportunity-cost calculator. Sums home and going-out drinking costs plus associated rideshare costs into monthly and yearly totals, then projects what that redirected spending could grow into if invested instead, using the future-value-of-an-annuity formula.

Tests a regular expression pattern against a string, guarded against catastrophic backtracking (ReDoS) by running the match in an isolated worker thread with a hard 500ms timeout that fails closed.