Traders and analysts cannot access reliable historical intra-day bid/ask spread data for backtesting and strategy development

Quantitative traders, algorithmic developers, and financial analysts need granular historical bid/ask price data at intra-day intervals to accurately backtest trading strategies and understand market microstructure, but publicly available data sources are fragmented, expensive, or lack the necessary historical depth and accuracy. Current solutions either charge prohibitively high fees, provide incomplete data, or require manual aggregation from multiple unreliable sources.