Resources
Data Captain Blog
Practical guides on US ETF APIs, backtesting, and portfolio analytics — written for developers, quants, and fintech builders.
- ETF APIdevelopersfintech
Best ETF APIs for Developers in 2026
Compare what developers need from an ETF data API — universe coverage, historical prices, backtesting, and pricing — and how Data Captain fits.
Data Captain Research Team8 min read - QQQhistorical returnsbacktesting
QQQ Historical Returns: Data, Backtests & API Access
How to analyze Invesco QQQ historical performance with real data — total return, drawdown, and a sample backtest using Data Captain.
Data Captain Research Team6 min read - SPYQQQVOOportfolio
SPY vs QQQ vs VOO: Which ETF Performed Better?
Compare three popular US equity ETFs over the same period using portfolio simulation — methodology and API approach with Data Captain.
Data Captain Research Team7 min read - ETF APIhistorical dataOHLCV
Historical ETF Data API: A Developer’s Guide
Learn what to look for in a historical ETF data API, including adjusted OHLCV, coverage, date handling, and backtesting readiness.
Data Captain Research Team8 min read - Yahoo Finance alternativeETF APIdevelopers
Yahoo Finance API Alternative for ETF Applications
Compare dependable approaches for replacing unofficial Yahoo Finance integrations in ETF dashboards, backtests, and fintech products.
Data Captain Research Team7 min read - ETF backtesting APIportfoliofintech
ETF Backtesting API: Build Reliable Investment Simulations
Understand ETF backtesting inputs, metrics, common data mistakes, and how to integrate a buy-and-hold simulation into an application.
Data Captain Research Team9 min read - ReactETF screenertutorial
How to Build an ETF Screener in React
Build a responsive React ETF screener with search, return filters, pagination, loading states, and a server-side ETF API.
Data Captain Research Team10 min read - SPY historical dataETF APIS&P 500
SPY Historical Data API for Developers
Retrieve SPY daily OHLCV data, validate market dates, and use the series for charts, indicators, and ETF backtests.
Data Captain Research Team6 min read - VOO historical dataETF APIVanguard
VOO Historical Data API: Prices, Returns, and Backtests
Use VOO historical price data in portfolio apps and compare Vanguard’s S&P 500 ETF against SPY and QQQ.
Data Captain Research Team6 min read - portfolio APIrebalancingETF
Portfolio Rebalancing API for ETF Applications
Turn current ETF holdings and target weights into transparent buy and sell recommendations with a portfolio rebalancing API.
Data Captain Research Team8 min read - market heatmap APIETFdashboard
Market Heatmap API for ETF Dashboards
Create ETF market heatmaps from cached return metrics, consistent baskets, and clear color scales.
Data Captain Research Team6 min read - technical indicators APIRSImoving averages
ETF Technical Indicators API: RSI, SMA, EMA, and MACD
Learn how technical indicator APIs derive RSI, SMA, EMA, and MACD from ETF closing-price history.
Data Captain Research Team9 min read - RSI APItechnical analysisETF
RSI API Guide for ETF and Investment Apps
Understand the Relative Strength Index calculation, required history, edge cases, and API response design.
Data Captain Research Team6 min read - SMA APIEMA APItechnical analysis
SMA and EMA API Guide for Market Applications
Compare simple and exponential moving averages and learn how to expose them consistently in an ETF API.
Data Captain Research Team6 min read - investment dashboardReactETF API
How to Build an Investment Dashboard with React and an ETF API
Plan and build an investment dashboard with ETF search, prices, charts, indicators, backtests, and portfolio analytics.
Data Captain Research Team11 min read - ETF CAGRreturnsportfolio analytics
How to Calculate ETF CAGR from Historical Prices
Calculate compound annual growth rate correctly from ETF start value, end value, and the exact elapsed time.
Data Captain Research Team5 min read - maximum drawdownETF riskbacktesting
How to Calculate Maximum Drawdown for an ETF
Measure the worst peak-to-trough decline in an ETF price or portfolio equity curve.
Data Captain Research Team6 min read - ETF comparisonperformanceportfolio
How to Compare ETF Performance Correctly
Compare ETF returns, risk, drawdowns, fees, and date coverage using a consistent analytical process.
Data Captain Research Team8 min read - free ETF APIdevelopersfintech
Free ETF API for Developers: What to Expect
Understand free ETF API limits, data coverage, authentication, and the path from prototype to production.
Data Captain Research Team6 min read - ETF data qualityAPI testingdevelopers
ETF API Data Quality Checklist for Production Apps
Use this checklist to validate ETF symbols, historical prices, freshness, duplicates, and API behavior before launch.
Data Captain Research Team7 min read - API paginationcachingETF API
ETF API Pagination and Caching Best Practices
Design faster ETF applications with stable pagination, debounced search, cache keys, and freshness-aware invalidation.
Data Captain Research Team7 min read