On usedby, 71 companies use Apollo and 48 use Clay. 4 companies use both, including Google, Okta, and Rippling. Apollo leads among the HR & Recruiting companies on usedby that use either tool, Clay among the Marketing Tech companies.Latest check Oct 5, 2026: 118 of 119 public lines checked. Counts include every proof level, job-post signals included. Companies named on both have a confirmed or observed line on each side.
Who uses Apollo, Clay, or both
Every company with a public proof for at least one of the two tools.
67
use only Apollo
4
companies use both
44
use only Clay
67 companies use only Apollo, 44 use only Clay and 4 use both, out of the 115 companies on usedby that use at least one of them.
Where it lands
Newest customers
No new customer since tracking started on October 4, 2026.
Where it lands
Newest customers
We have not started tracking changes for Clay yet.
Who uses both
Companies with a confirmed or observed line on both tools.
| Company | First public proof, Apollo |
|---|---|
 Google | On or before Nov 2024 |
 Okta | — |
 Rippling | — |
 Mutiny | On or before Nov 2024 |
By industry
Which tool the companies on usedby use, by industry. Shares of the companies on usedby that use Apollo, Clay or both: a share of the companies on usedby, not of the market.
Apollo onlyBothClay only
More common with Apollo
- HR & Recruiting6 of the 8 HR & Recruiting companies on usedby that use either tool use Apollo, 1 of them alongside Clay.
- Data & Analytics3 of the 5 Data & Analytics companies on usedby that use either tool use Apollo.
More common with Clay
- Marketing Tech7 of the 9 Marketing Tech companies on usedby that use either tool use Clay, 1 of them alongside Apollo.
- Artificial Intelligence7 of the 8 Artificial Intelligence companies on usedby that use either tool use Clay, 1 of them alongside Apollo.
- DevTools & Infrastructure5 of the 8 DevTools & Infrastructure companies on usedby that use either tool use Clay.
Source: confirmed and observed usedby lines. Job-post signals, the weakest proof level, are left out of these shares.
Side by side
Facts from our data and from each vendor's public pages. Each line says where it comes from.
ApolloClayWhat customers report
Results as the vendor or the customer published them, with the source and the date.
Apollo
No reviewed story for Apollo yet.
Clay
new reps were revenue-generating 6x faster than before Clay
Pump
Vendor case study, clay.com, captured Oct 5, 2026
a 15% increase in enterprise meetings booked
Merge
Vendor case study, clay.com, captured Oct 5, 2026
Questions about Apollo and Clay
Which is used more, Apollo or Clay?
Apollo has more customers on usedby: 71 against 48 for Clay. Apollo leads among the HR & Recruiting companies on usedby that use either tool, Clay among the Marketing Tech companies.
Do companies use both Apollo and Clay?
Yes. 4 companies use both on usedby, including Google, Okta, and Rippling.
Who uses Apollo?
71 companies on usedby, each with the public page that shows it. See who uses Apollo.
Who uses Clay?
48 companies on usedby, each with the public page that shows it. See who uses Clay.
How does usedby count customers?
A company counts when a public page shows it: a vendor's customer page, a case study, a press release or a job post, most saved with a dated capture. Every line is a customer, at one of three proof levels: confirmed, observed or signal (a job post, the weakest). A company is named as using both tools when its lines on both are confirmed or observed.