Scanners 101

An overview of the three scanner types in Scanz — Data, Signal, and News — and the mental model for when to reach for each.

Scanz has three scanners. They share a filter engine and look similar at first glance, but each one answers a different question about the market. The point of this page is to draw the lines clearly so you know which one to reach for in any given moment — the how-to for each one lives in its own guide.

If you’re new to Scanz, read this before diving into the individual scanner docs. Five minutes here saves a lot of confusion later.

The three scanners at a glance

Scanner	The question it answers	The output
Data Scanner	What stocks match my criteria right now?	A live, updating list of every matching stock.
Signal Scanner	What just happened?	A stream of discrete events as they fire.
News Scanner	What’s the catalyst on stocks I’d care about?	A filtered news feed scoped to stocks matching your filters.

Same filter engine — the same 65+ filters work in all three. Different shape of output. Different reason to use them.

The Data Scanner: a snapshot of now

The Data Scanner is what most traders mean when they say “scanner.” You define a set of criteria — say, price between $1 and $20, gapped up 10%+ pre-market, volume over 200K — and the scanner shows you every stock currently matching, updating twice per second.

The key word is currently. A stock leaves the result set the moment it stops matching. There’s no event log, no history. If a stock met your criteria at 9:30 AM but doesn’t anymore by 9:35 AM, it’s gone. What you see is the current state of the filtered universe.

This makes the Data Scanner a tool for discovery and surveying:

Building a pre-market watchlist — open a gappers prebuilt, see who’s moving, send the interesting ones to a watchlist.
Surveying market character — scan for stocks above VWAP with rising volume, get a sense of how many there are and whether momentum is broad or narrow.
Prospecting for setups — define what your trade looks like in filter form, and the scanner shows you which stocks fit it right now.

The Data Scanner is the most-used surface in Scanz. If you only ever opened one, this is the one. Full guide: Data Scanner.

The Signal Scanner: what just transitioned

The Signal Scanner runs on the same filter engine but watches for events, not states. An event is a transition — a stock crossing above VWAP for the first time today, printing a new 52-week high, completing a sequence of three green candles, rotating 50% of its float. Each event is a discrete moment, not an ongoing condition.

The distinction between the Data Scanner and the Signal Scanner is timing. The Data Scanner tells you a stock is currently above VWAP. The Signal Scanner fires the instant it crossed VWAP, which might have been an hour ago and still be true now. For trading, that timing edge is often what you’re paying for — knowing the exact moment a setup formed.

Reach for Signals when:

Timing matters. You want to catch the moment a stock breaks a level, not see it after the fact.
You’re watching for transitions. Crossovers, reversals, breakouts — anything that’s defined by a change rather than a state.
You want a stream, not a snapshot. Signals accumulate. Each row is something that fired, kept around as a record.

There are 14 event types Signals can detect, and you combine each one with the same filters as the Data Scanner to control which universe of stocks the events fire from. Full guide: Signal Scanner.

The News Scanner: catalysts on candidates

The News Scanner aggregates headlines from 97+ sources — newswires, SEC filings, exchange releases, financial press — and runs them through the same filter engine the price scanners use. The unique idea: filter news by stock characteristics, not by keyword.

Most news feeds give you two bad options. Watch all news and drown in irrelevant headlines, or limit to a watchlist and miss news on stocks you haven’t discovered yet. The News Scanner solves that — show me headlines, but only on stocks gapping 10%+ pre-market with 500K+ volume. Or only on stocks with float under 20M and a halt today. The headlines that survive the filter are pre-qualified for the kind of setup you trade.

You can also filter by news type (earnings, upgrades, mergers, halts, FDA, biotech, etc.) and by headline keywords, on top of the stock filters. That gives you precise control over both the universe and the catalyst type.

Reach for News when:

You want context attached to candidates. The Data Scanner finds the stock; News tells you why it’s moving.
You’re tracking specific catalysts. FDA news on biotech, earnings on small caps, halts and resumes on momentum tickers.
You want headline-driven discovery. Sometimes the news is the setup — a halt resuming, a contract win, a reverse split — and you want to surface those headlines on your kind of stocks.

Full guide: News Scanner.

How they fit together

A common end-to-end workflow strings all three:

Pre-market — Data Scanner. Open a gappers scan. The result is a list of 10–30 stocks moving on something. Promote the interesting ones to a watchlist.
News Scanner — scoped to that watchlist. Why is each one moving? Filter News to your watchlist and see the catalysts side by side. Now you have setups and reasons.
Market open — Signal Scanner. Watch for breakout or reversal events on the same watchlist. You’re not surveying the whole market anymore — you’re waiting for triggers on stocks you’ve pre-qualified.

That’s the loop. Data scanner discovers, News explains, Signal scanner times.

Filter engine: the common foundation

The thing that makes the three scanners work as a system is that they share the same filter engine. A filter you understand from the Data Scanner — say, Volume PM >= 100000 — works the same way in the Signal Scanner and the News Scanner. The same operators, the same session codes (PM/RH/AH/FD), the same offset notation for comparing periods.

This means once you’ve built mental fluency with one scanner, you’ve built it with all three. The only thing that changes between them is the shape of the output: a list, a stream of events, or a feed of headlines.

For the full filter reference, see References.

A common mistake to avoid

A surprising number of new traders use the Data Scanner for things that are really Signal Scanner jobs, and vice versa. Two examples:

“I want to be alerted when a stock breaks above VWAP.” This is a Signal Scanner job. The Data Scanner shows you stocks currently above VWAP — by the time you notice them, they’ve been above VWAP for a while.
“I want to see all the stocks gapping 10%+ in pre-market.” This is a Data Scanner job. Signals would fire the moment each stock crossed 10%, but you’d miss any that were already past 10% by the time you looked.

Rule of thumb: if you’re asking “what’s already true?” use the Data Scanner. If you’re asking “what just happened?” use the Signal Scanner. If you’re asking “what’s the catalyst?” use the News Scanner.

Where to go next

Data Scanner — Full guide to building scans, including all 65+ filters.
Signal Scanner — The 14 event types and how to configure them.
News Scanner — Filter aggregated news by stock criteria.
Concepts — How scanners fit with Alerts and Watchlists in the broader workflow.

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