What is the Source layer?

Where raw records enter: companies, people, firmographics, scraped listings. It serves Identity in the eight-layer model of revenue architecture. Nothing downstream is better than what you let in.

Which tools do operators run in the Source layer?

13 tools are placed in the Source layer, 11 of them named by an operator running them in a working system. The most-named are Apollo (6 operators), Apify (2 operators), Lead Magic (2 operators), ZoomInfo (2 operators) and ContactOut (1 operator).

How does a tool get placed in the Source layer?

A tool is placed by the function it performed in a named operator's system, described on a Show Me Your Stack or GTM Vault Podcast episode, or by a GTM Vault essay recommendation. The two grades are shown separately and never blended. Placement is not for sale.

The Stack Index / Source

serves Identity

Source

Where raw records enter: companies, people, firmographics, scraped listings.

Nothing downstream is better than what you let in.

Updated 24 Sep 2026, the date of the latest episode citing a tool in this layer. Cite as: GTM Vault, The Stack Index, “Source”, https://pro.gtmvault.co/stack/layer/source, updated 24 Sep 2026.

13tools placed

11operator verified

2author recommended

Apollo6 ops

Contact data and email enrichment via API. Alexander Shartsis, Skyp, SMYS 2

Self-serve

Apify2 ops

Pre-built actor aggregating review sites. Vinayak Mishra, Slang AI, SMYS 1

Self-serve

Lead Magic2 ops

First call in the enrichment waterfall. Garrett Wolfe, OneGTM, SMYS 3

Self-serve

ZoomInfo2 ops

Account and contact data at SecureAuth, in heavy use. Mark van Oppen, SecureAuth, Confirmed Sep 2026

Enterprise

ContactOut

Contact data alongside Apollo. Charles Cormier, TopLeads, GTM 19

Self-serve

HG Insights

Firmographic waterfall alongside ZoomInfo and Clay. Umar Farooq Adam, Hitachi Vantara, SMYS 5

Enterprise

LinkedIn Sales Navigator

Research and prospecting. Garrett Wolfe, OneGTM, SMYS 3

Mid-market

Persana

Lead intelligence feeding outbound. Charles Cormier, TopLeads, GTM 19

Mid-market

Prospeo

Named as a likely vendor in the email waterfall. Tim Scheuer, Oxygen, SMYS 6

Self-serve

Serper.dev

Google Maps scraping for venue discovery. Vinayak Mishra, Slang AI, SMYS 1

Self-serve

Vieu

Relationship paths into enterprise accounts at SecureAuth, in heavy use. Mark van Oppen, SecureAuth, Confirmed Sep 2026

Enterprise

FullEnrichauthor

Cascading enrichment chain. Rick Koleta, Three Stages

Self-serve

Wizaauthor

Contact verification in the cascade. Rick Koleta, Three Stages

Self-serve

Common questions

What is the Source layer?: Where raw records enter: companies, people, firmographics, scraped listings. It serves Identity in the eight-layer model of revenue architecture. Nothing downstream is better than what you let in.
Which tools do operators run in the Source layer?: 13 tools are placed in the Source layer, 11 of them named by an operator running them in a working system. The most-named are Apollo (6 operators), Apify (2 operators), Lead Magic (2 operators), ZoomInfo (2 operators) and ContactOut (1 operator).
How does a tool get placed in the Source layer?: A tool is placed by the function it performed in a named operator's system, described on a Show Me Your Stack or GTM Vault Podcast episode, or by a GTM Vault essay recommendation. The two grades are shown separately and never blended. Placement is not for sale.

Counted with the layers next to it

The source layer is one part of a working system. These pages rank every tool across this layer and the ones it runs with, by how many operators described running each.

The enrichment and data tools operators run, by operator count · The outbound tools operators run, by operator count

New operator stacks, as they are published

Every Show Me Your Stack episode adds operators and tools to this index. Subscribe to GTM Vault and get each one as it lands.

All layers · What the layers mean · Enrichment and Resolution →