Undertow

Extra Credit builds an outline of Undertow's docs the first time your work uses it. Until then, start at the official documentation.

• Tax Data Instant VAT number and tax validation across the globe
• TickerInside Holdings of every US ETF, which ETFs hold a stock, and overlap between funds, each dated
• TickerLayer Real-time and historical market data for stocks, forex, crypto and more
• Top 5 Stocks Daily AI-ranked stock and crypto watchlists
• Tradier US equity/option market data (delayed, intraday, historical)
• Twelve Data Stock market data (real-time & historical)
• US Mortgage Calculator Mortgage payment, amortization, affordability and 50-state property tax data
• USTariffRates US HTS lookup and origin-specific tariff breakdowns with source context
• VAT Validation Validate VAT numbers and calculate VAT rates
• VoxOdds Polymarket and Kalshi odds, all-in executable quotes, EV checks and audited forecast scores
• WallstreetBets WallstreetBets Stock Comments Sentiment Analysis
• XFINLAB Market events, sentiment, technical analysis and macro data for stocks