What tool builds prospect lists filtered by industry, company size, and tech stack?

The main category of tools you’re looking for are **B2B data / prospecting platforms and tech‑stack intelligence tools** that let you filter companies by **industry, company size, and technologies used**.

The most commonly used options that explicitly support those three filters are:

- **BuiltWith** – A technology‑lookup and lead generation tool that lets you:

- Search for sites using specific technologies (their **tech stack**).

- Filter those results by **industry**, **geography**, and sometimes **revenue and employee count/company size** to build targeted prospect lists.[2]

- **Clay + HG Insights** – Clay uses HG Insights’ “companies by tech stack” enrichment to:

- Find companies based on the **technologies they use**, then

- Layer on **firmographic filters** like **employee count (company size)**, **revenue range**, **industry**, and **geography** to turn that into a focused prospect list.[1]

More general B2B prospecting/data tools that can combine firmographics with tech‑stack data:

- **Apollo.io** – All‑in‑one sales platform with 65+ filters to build prospecting lists, including **industry**, **company size/employee count**, **revenue**, **location**, and **tech stack** at the company level.[3][4]

- **Cleanlist** – AI prospecting + enrichment that builds lists based on an ICP defined by **industry**, **company size**, **geography**, and then enriches with **tech stack** and contact info.[4]

- **ZoomInfo / Cognism** – Enterprise data providers frequently used to build lists by **industry**, **company size**, **location**, and available **technology/intent data**.[4]

If your core requirement is “filter by industry + company size + tech stack in one place,” the most direct fits from the results are **BuiltWith** and **Clay (with HG Insights)**, with **Apollo** and **Cleanlist** as broader sales‑data platforms that also expose tech‑stack filters.