About PatternsRadar
What this is
PatternsRadar is a stock screener for the National Stock Exchange of India, built around one question most screeners cannot answer: does this scan actually work? Every scan here can be replayed across the last 250 sessions to measure its hit rate before anyone trusts it with money. It is built and operated by Bitmask, a small Indian software company.
Where the data comes from
Price, volume and delivery data come from the open-source eod2 dataset — NSE daily bars already adjusted for splits and bonuses, the single hardest part of an Indian market dataset to get right. The database covers 3,500+ instruments and about 8.2 million daily bars, back to 1995 for the oldest listings. It is rebuilt every trading evening after the close; a build that fails any verification gate leaves the previous day’s data serving untouched rather than serving a half-built one.
Those figures originate in the end-of-day files published by the National Stock Exchange of India. PatternsRadar is not affiliated with, endorsed by or licensed by NSE, and exchange and index names are used here only to describe what the data covers.
How the numbers are checked
All 42 indicator columns are verified against pandas-ta-classic — the standard Python implementations — to within one millionth, on every build. The query language’s 70 reference scans are compiled and run in CI, and each of the sugar operators is proven to return exactly the same stocks as the same condition written longhand. A documentation example that stops compiling fails the build instead of misleading a reader.
What it deliberately does not do
There is no intraday data and no live feed: the dataset updates once per session, after the close, so alerts are end-of-day by design. There is no BSE coverage. Fundamentals are point-in-time and screenable — P/E, market cap, growth, shareholding — but their filings backfill is in progress, so a stock without parsed results shows nothing rather than a guess; sector classification is today’s snapshot with no history. F&O data is per-stock aggregates (OI, basis, put-call ratios), not option chains. The hit-rate replay is a sketch, not a full backtest: close-to-close returns, no costs, no slippage, and the interface says so wherever the numbers appear. PatternsRadar is a research tool; nothing on it is investment advice or a recommendation to buy or sell anything.
Contact
Questions, corrections and bug reports are welcome — reach us through bitmask.in. If a number here looks wrong, we want to know more than you want to tell us.