A stock screener filters thousands of stocks down to the handful that match your criteria. Add real-time alerts and it notifies you the moment a stock enters your filter — without you having to check manually every hour.

Most stock screeners filter on price, volume, and technical indicators. The best ones go further — flagging insider buys, unusual options activity, and news-driven momentum before they show up in price action. This guide ranks the best free options by what matters: alert speed, filter depth, and whether they actually catch moves before the crowd.

The Problem With Most Stock Screeners

Standard screeners filter on output — what has already happened in the price. RSI below 30 means the stock already dropped. A 52-week high means it already moved. You are reacting to history.

The most powerful screeners surface leading indicators — signals that precede price moves rather than follow them. SEC Form 4 insider purchases, unusual options volume spikes, and social mention velocity are all leading. Price crossovers are lagging.

The key distinction: A screener that catches a 52-week breakout tells you where a stock has been. A screener that catches a CEO buying $1M of their own stock tells you where it might be going.

Best Free Stock Screeners With Alerts

Finviz
The most popular free stock screener. 60+ technical and fundamental filters covering RSI, P/E ratio, EPS growth, insider ownership, and more. The free tier is delayed 15–20 minutes and does not include real-time alerts. Finviz Elite adds real-time data and email alerts. Best for fundamental + technical filtering.
60+ filtersHeatmap viewFree to start Alerts require paid tierNo insider filing integrationNo options flow
TradingView
Best-in-class charting with a built-in screener and price alert system. Free tier includes basic price and indicator alerts (limited to 1 alert). Pro tiers add unlimited alerts, real-time data, and multi-timeframe screener access. Better for chart-based technical traders than for fundamental screening.
Best chartsPrice alerts on free tierHuge community 1 alert limit on free tierNo insider/options data
Barchart
Free / Premier $19.99/mo
Strong options-specific screening with volume/OI ratio filters and unusual activity detection. The free tier includes basic alerts. Good coverage of options flow unusual activity — helpful for identifying stocks with elevated call buying. No insider filing integration.
Options screening freeUnusual activity filter No insider dataUI is dated
OpenInsider
100% Free
Dedicated SEC Form 4 screener. Filter insider purchases by transaction type (open-market only), dollar size, role (CEO/CFO), and cluster buying. No real-time alerts built in — designed for manual research. Best used alongside a general screener to verify insider activity on stocks you are already watching.
Best insider filteringCompletely free No automatic alertsStocks only (no crypto)
SniperMachine
100% Free
Not a traditional screener — it continuously monitors SEC EDGAR, options flow, Reddit mention velocity, news sentiment, technical levels, funding rates, and Fear & Greed across all US stocks and major crypto. When multiple signals converge on one ticker and the AI score exceeds 65/100, an alert fires. Delivered to Telegram in real time. Full track record of every alert published publicly.
8 signal layersReal-time Telegram alertsNo account required Public track recordCrypto + stocks No manual filter customization

Which Screener for Which Trader

The Alert Speed Problem

Even a 15-minute data delay makes a real difference in fast-moving markets. If a CEO files a Form 4 at 9:02 AM and it takes you until 9:20 AM to see it because your screener uses delayed data, the stock may have already moved 3–5% by the time you act.

Real-time monitoring — scanning live EDGAR feeds, live options tape, and live news — is the only way to act before the majority of retail traders. SniperMachine's monitoring runs continuously, 24 hours a day, with no polling delay.

Get Multi-Source Stock Alerts Free

SniperMachine monitors insider filings, options flow, Reddit velocity, and 5 more sources — and fires a Telegram alert when they converge. Every alert is public with its outcome.

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Frequently Asked Questions

What is a stock screener?
A stock screener filters the entire stock market by criteria you set — price range, volume, sector, RSI, earnings growth, etc. — and returns a list of stocks that match. Screeners with alerts notify you automatically when a stock enters your filter criteria.
What is the best free stock screener?
Finviz is the most popular free screener for technical and fundamental filters. TradingView is best for charting with price alerts. SniperMachine goes further — it screens for insider buys, options flow spikes, and social velocity rather than just price and volume.
Do free stock screeners have real-time alerts?
Finviz Elite has real-time alerts for $24.96/month. The free Finviz tier is delayed 15–20 minutes. TradingView free tier includes basic price alerts. SniperMachine's free tier fires alerts based on fundamental catalysts — insider buys, options flow, news — in real time with no subscription required.

Disclaimer: Nothing here constitutes financial advice. All trading involves risk of loss.