ChartingLens wins as the best free, all-in-one screener — real-time charts, a proprietary AI ranking score, backtesting, and insider-trading data, with a usable free tier that doesn't require a card. Prospero.ai wins as a free mobile-first app built specifically around institutional options flow, dark pool activity, and social sentiment rather than traditional technical filters. Trade Ideas wins on raw scanning power for active intraday traders — its Holly AI evaluates thousands of setups per second — but it costs roughly 5-6x what the other two charge, so the price only makes sense once you're trading actively enough to need it. An AI screener's real advantage over a traditional filter isn't just showing which stocks match your criteria — the better platforms explain why a setup ranks highly, based on real historical pattern data.
Where each one actually wins
ChartingLens combines a server-side screener with 20+ fundamental, momentum, and technical filters and a proprietary "CL Score" that ranks stocks by price position relative to moving averages, RSI trend, and recent volume patterns. It's free forever without a card, covering real-time stocks and crypto data, insider tracking, and two AI credits a day before you'd need to pay for more.
Prospero.ai takes a different data angle entirely: institutional options flow, dark pool activity, and real-time social sentiment, packaged into a free mobile app rather than a desktop charting platform. It's the pick if you want signals based on what large players and social sentiment are doing, not classic technical indicators.
Trade Ideas is built for genuinely active intraday trading — its Holly AI evaluates thousands of setups per second and streams ranked ideas throughout the session, with backtesting and auto-trading on top. At roughly $84/month, it's a real commitment that only pays for itself if you're trading frequently enough to need that scanning speed.
Quick comparison
| Tool | Core signal | Starting price | Best fit |
|---|---|---|---|
| ChartingLens | Technical + fundamental ranking score | Free | Best free, all-in-one starting point |
| Prospero.ai | Institutional flow + social sentiment | Free | Mobile-first, sentiment-driven signals |
| Trade Ideas | Real-time intraday scanning (Holly AI) | ~$84/mo | Active traders who need scanning speed |
Which one should you actually use?
Start with ChartingLens for free, all-in-one screening with a genuinely useful AI ranking layer on top of standard filters. Add Prospero.ai if you specifically want institutional flow and sentiment data as a second signal, also for free. Move to Trade Ideas only once you're trading actively enough intraday that its scanning speed and backtesting justify the price.
FAQ
Can an AI stock screener actually predict which stocks will go up? No — it identifies stocks matching historically favorable patterns or unusual activity, which is different from predicting future price movement with certainty. Treat any AI signal as one input into your own research, not a guarantee.
Are free stock screeners like ChartingLens and Prospero.ai missing anything important? Mainly scanning speed and depth — free tiers cover most retail investors' needs well, but very active intraday traders eventually hit limits (screener result caps, fewer AI credits) that push them toward a paid tool like Trade Ideas.
Is dark pool and options flow data from Prospero.ai actually reliable? It reflects real institutional activity, but interpreting it correctly takes practice — a large options trade or dark pool print doesn't always mean what casual interpretation assumes, so treat it as one data point rather than a standalone signal.
Do I need a brokerage account connected to use these screeners? No, all three work as standalone research and screening tools independent of your broker — you still place trades through your actual brokerage account separately.
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*Ratings and pricing reviewed monthly. Last updated September 2026.*
Bogdex · Founder & editor, woska
Bogdex builds and curates woska, testing AI tools against real workflows to judge which ones actually save time rather than which have the longest feature list.