How to evaluate a stock scanner: 4 questions before you pay.

I've signed up for almost every prosumer stock scanner since 2018. Most fail the same way: the tool is fine for a week, then you realise you have no way to tell whether the calls it surfaces are actually working. By month three you've added it to the pile of $20-$50/month subscriptions you keep forgetting to cancel.

If you're shopping for a scanner, these four questions will save you the cycle:

1. Can you see why a stock scored the way it did?

If a tool gives you one number and no reasons, you can't tell whether it is working, or whether it will still work next month. Tapeline names the six things its score looks at, and each stock's page shows its score on every one of them (how the score works).

2. What does the data come from?

"AI-powered signals" usually means "we bought a feed from a third-party market-data feed and slapped a score on top." Which is fine — that's also our spine. But know it. Bloomberg Terminal at $32k/yr uses similar feeds; the premium is the speed and breadth of their proprietary chat and curated news, not the raw data. Anyone charging $200/month for "exclusive AI signals" is reselling a third-party market-data feed and a third-party data feed.

3. Is the cheapest tier real?

Test it. If the free or cheapest paid tier strips out so many features the product is unusable, the team is incentivised to upgrade-trap rather than retain.

4. Can you cancel online, without emailing anyone?

If you have to email support to cancel, that's a tell about how the team treats you generally. A Stripe-portal-style cancel, online and any time, is table stakes; if it's not there, leave. (Yes, ours is.)