CoreWeave vs OpenAI API: who uses which
Customers, public proof and the companies that use both.
On usedby, 18 companies use CoreWeave and 37 use OpenAI API. 1 company uses both, including Mercado Libre. CoreWeave leads among the Artificial Intelligence companies on usedby that use either tool, OpenAI API among the DevTools & Infrastructure companies.Latest check Oct 18, 2026: 54 of 55 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 CoreWeave, OpenAI API, or both
Every company with a public proof for at least one of the two tools.
17
use only CoreWeave
1
company uses both
36
use only OpenAI API
17 companies use only CoreWeave, 36 use only OpenAI API and 1 uses both, out of the 54 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, OpenAI API |
|---|---|
 Mercado Libre | On or before Oct 2026 |
By industry
Which tool the companies on usedby use, by industry. Shares of the companies on usedby that use CoreWeave, OpenAI API or both: a share of the companies on usedby, not of the market.
CoreWeave onlyBothOpenAI API only
More common with CoreWeave
- Artificial Intelligence8 of the 12 Artificial Intelligence companies on usedby that use either tool use CoreWeave.
More common with OpenAI API
- DevTools & Infrastructure6 of the 7 DevTools & Infrastructure companies on usedby that use either tool use OpenAI API.
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.
CoreWeaveOpenAI APIWhat customers report
Results as the vendor or the customer published them, with the source and the date.
CoreWeave
The team went from POC to production in three weeks.
Mercado Libre
Vendor case study, wf.coreweave.com, published Jul 2, 2026
saving 75% in cloud costs
NovelAI
Vendor case study, wf.coreweave.com, published Oct 6, 2026
OpenAI API
No reviewed story for OpenAI API yet.
Questions about CoreWeave and OpenAI API
Which is used more, CoreWeave or OpenAI API?
OpenAI API has more customers on usedby: 37 against 18 for CoreWeave. CoreWeave leads among the Artificial Intelligence companies on usedby that use either tool, OpenAI API among the DevTools & Infrastructure companies.
Do companies use both CoreWeave and OpenAI API?
Yes. 1 company uses both on usedby, including Mercado Libre.
Who uses CoreWeave?
18 companies on usedby, each with the public page that shows it. See who uses CoreWeave.
Who uses OpenAI API?
37 companies on usedby, each with the public page that shows it. See who uses OpenAI API.
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 four proof levels: confirmed, declared by the company itself, 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.