Every e-commerce category has gaps — subcategories where buyer demand exists but product supply is weak. These gaps are invisible if you only look at bestseller lists. They become obvious when you compare category data across platforms.

Here is how to systematically find category gaps — and why most sellers miss them entirely.

What a Category Gap Looks Like

A category gap has three characteristics:

1. Strong demand signal: Monthly search volume for category keywords is above 10,000 and growing.
2. Weak supply signal: Fewer than 50 active listings on the target marketplace, or the top 10 listings control over 80% of category sales (indicating limited competition rather than a healthy market).
3. Price compression missing: The price range is narrow — most products cluster within a 15% price band. This means sellers are copying each other rather than differentiating. A wide price spread signals healthy segmentation.