CLIENT-SIDE BACKTESTING ENGINE v1.0

Designed for absolute speed. Built for clarity.

Portfolio Visualizer is a hyper-optimized historical backtesting tool engineered to provide instant asset tracking without any server overhead, logins, or tracking cookies.

Our Mission

Financial backtesting tools are often slow, cluttered with ads, and locked behind expensive paywalls. We created Portfolio Visualizer to give retail investors a lightning-fast, premium-tier, and completely free alternative. By executing all portfolio simulations directly in your browser, we deliver instantaneous returns rendering and eliminate server-side security risks.

Supported Historical Assets

Our calculator engine references a curated matrix of historical returns spanning the last 20 years (2006–2025). This dataset represents the foundation of modern multi-asset portfolios:

S&P 500 (SPY): Measures the performance of 500 leading publicly traded companies in the United States, representing the gold standard for equity growth.
Bitcoin (BTC): Captures the emergence and growth of the world's first decentralized digital currency, showcasing hyper-growth and high-volatility profiles.
Gold (GLD): The traditional safe-haven physical commodity used by investors to hedge against inflation and market downturns.
US Treasury Bonds (10-Year): Representing defensive fixed-income securities backed by the full faith and credit of the US government.

Mathematical Methodology

When you adjust the asset allocation sliders, our client-side engine calculates the annual growth of your investment using the formula:

Investment(t) = Investment(t-1) × [ Σ (Asset_Allocation_i × (1 + Return_i,t)) ]

Where Asset_Allocation_i is your chosen percentage for asset i (summing to 100%), and Return_i,t is the annual percentage return of asset i in year t. The values are compounded yearly to trace your portfolio's cumulative growth over the selected timeframe.

Why We Choose 100% Client-Side

By utilizing vanilla client-side JavaScript, we achieve zero server latency. There is no server API call required to update your portfolio chart. This architecture guarantees a perfect Core Web Vitals score, loading the entire tool in under 100 milliseconds and maintaining responsiveness even on ultra-low-bandwidth mobile connections.