Choosing a stock screener: what to look for

Chartink earned its place: it made NSE screening free, fast, and shareable, and its library of public scans taught a generation of Indian traders what a screener even is. If you are reading this, you have probably also met its ceiling — and the most common reason traders go looking elsewhere is that a scan's history is a list of names, and what they want is a result.

Whatever you evaluate — including PatternsRadar, which this site is, so weigh the source accordingly — these are the five capabilities that actually separate screeners.

1. Can it tell you what happened after the match?

Every screener answers "who matches today?" Several will also replay a scan across past sessions and list what matched — Chartink has done that since 2019, nine years deep on daily bars, for free. Far fewer answer the question that decides whether the scan is worth running: "when this matched in the past, what happened next?"

Watch for the difference, because both get called backtesting. A trigger history hands you symbols and dates; an outcome measurement attaches prices to them — hit rate, average return, over a stated holding period. Without the second, scan-building is folklore: you run "RSI below 30" because a book said so, not because you have seen how its matches did on NSE stocks. With it, every scan becomes a testable claim you keep or discard on evidence. On every scan page here — the 52-week high breakout, say — the hit-rate panel reports what matches did over the next 1, 5 and 20 days. It is the single feature we would not give up, and the first thing to demand from any screener you evaluate.

2. Can it express conditions about time?

Form-based screeners handle snapshots well: RSI below 30, price above the 200-DMA. The conditions that actually describe setups are about sequence and persistence, and most tools cannot say them at all:

rsi(14) crossed above 30 within 3 bars
close has been above ema(21) for 10 bars
volume rising for 3 bars
close is highest in 52w

When a screener lacks event operators like these, users fake them with towering stacks of offset comparisons — that is what most complex Chartink scans are. A readable query language is not cosmetic; it determines which questions you can ask, and whether you can still understand your own scan six months later.

3. Does it treat delivery percentage as a first-class field?

Delivery data — what fraction of traded volume was actually taken home — is unique to Indian exchanges and is the closest public thing to seeing conviction directly. Most screeners bury it as a column. It belongs in scan logic, combinable and backtestable like any other field: delivery surge with a price move is a different and better signal than either input alone. The delivery scan family shows the range of what it can express.

4. How deep and how honest is the data?

Two questions expose most tools. How far back does daily history go — enough to test a scan across regimes, or just a recent window? And is it split-adjusted properly — because one unadjusted bonus issue in the lookback quietly poisons every moving average and every backtest that touches it. (Here: 30 years, split-adjusted, refreshed after each close.)

5. Can you get results out programmatically?

If a screener is part of your process, its results end up needing to reach your process — a script, a sheet, an alert pipeline, an AI agent. An API turns a screener from a website into an ingredient; the MCP endpoint here exists so agent tools can run scans directly.

The honest comparison

Chartink remains stronger on four things: real-time intraday scanning, a decade of community scans, universal familiarity, and a trigger history that reaches nine years back against the one year replayed here. If your process is built on intraday triggers, it may still be the right tool — our data is end-of-day by design.

If your horizon is daily bars and your standard is "show me what the matches did", that is the gap this product was built to close. The feature-by-feature comparison is maintained separately; the shorter version is: run any scan here, open its hit-rate panel, and decide whether you can go back to screening without one.