C3 AI vs StackAI: who uses which
Customers, public proof and the companies that use both.
On usedby, 44 companies use C3 AI and 21 use StackAI. 1 company uses both, including BAE Systems. C3 AI leads among the Aerospace & Defense companies on usedby that use either tool, StackAI among the Banking & Mortgages companies.Latest check Oct 11, 2026: 65 of 65 public lines checked. Counts include every proof level, job-post signals included. A company on both tools counts at any proof level, and a job post on one side is marked as such.
Who uses C3 AI, StackAI, or both
Every company with a public proof for at least one of the two tools.
43
use only C3 AI
1
company uses both
20
use only StackAI
43 companies use only C3 AI, 20 use only StackAI and 1 uses both, out of the 64 companies on usedby that use at least one of them.
Who uses both
Companies with a public line on both tools, at any proof level: the strongest proofs come first, and a job post is marked.
| Company | First public proof, C3 AI | First public proof, StackAI |
|---|---|---|
 BAE Systems | On or before Oct 2026 | On or before Oct 2026 |
By industry
Which tool the companies on usedby use, by industry. Shares of the companies on usedby that use C3 AI, StackAI or both: a share of the companies on usedby, not of the market.
C3 AI onlyBothStackAI only
More common with C3 AI
- Aerospace & Defense8 of the 8 Aerospace & Defense companies on usedby that use either tool use C3 AI, 1 of them alongside StackAI.
- Energy, Utilities & Cleantech8 of the 8 Energy, Utilities & Cleantech companies on usedby that use either tool use C3 AI.
- Government & GovTech5 of the 6 Government & GovTech companies on usedby that use either tool use C3 AI.
More common with StackAI
- Banking & Mortgages3 of the 5 Banking & Mortgages companies on usedby that use either tool use StackAI.
Source: every usedby line, from confirmed proofs to job-post signals (the weakest proof level).
Side by side
Facts from our data and from each vendor's public pages. Each line says where it comes from.
C3 AIStackAIWhat customers report
Results as the vendor or the customer published them, with the source and the date.
C3 AI
In just 4 weeks, C3 AI configured the C3 AI Supply Network Risk application for 42 critical ventilator SKUs (stock keeping units)
Global HealthTech Company
Vendor case study, c3.ai, captured Oct 9, 2026
99% reduction in the time to generate threat data, from weeks to minutes
Missile Defense Agency
Vendor case study, c3.ai, captured Oct 8, 2026
StackAI
60% cost reduction in applicant evaluation
Nova Talent
Vendor case study, stackai.com, captured Oct 8, 2026
800+ hours saved by eliminating repetitive manual research
Varos
Vendor case study, stackai.com, captured Oct 8, 2026
Questions about C3 AI and StackAI
Which is used more, C3 AI or StackAI?
C3 AI has more customers on usedby: 44 against 21 for StackAI. C3 AI leads among the Aerospace & Defense companies on usedby that use either tool, StackAI among the Banking & Mortgages companies.
Do companies use both C3 AI and StackAI?
Yes. 1 company uses both on usedby, including BAE Systems.
Who uses C3 AI?
44 companies on usedby, each with the public page that shows it. See who uses C3 AI.
Who uses StackAI?
21 companies on usedby, each with the public page that shows it. See who uses StackAI.
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 counts as using both tools when it has a line on each, at any level; the list shows the strongest proofs first and marks job posts.