Gemini vs OpenAI API: who uses which
Customers, public proof and the companies that use both.
On usedby, 2 companies use Gemini and 5 use OpenAI API. No company is listed with both yet.Latest check Oct 7, 2026: 6 of 7 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 Gemini, OpenAI API, or both
Every company with a public proof for at least one of the two tools.
2
use only Gemini
0
companies use both
5
use only OpenAI API
2 companies use only Gemini, 5 use only OpenAI API and 0 use both, out of the 7 companies on usedby that use at least one of them.
Where it lands
Newest customers
No new customer since tracking started on October 7, 2026.
Where it lands
Newest customers
We have not started tracking changes for OpenAI API yet.
Who uses both
Companies with a confirmed or observed line on both tools.
Side by side
Facts from our data and from each vendor's public pages. Each line says where it comes from.
Gemini
OpenAI APIPricing, security and data residency are not checked yet. usedby adds them from each vendor's public pages, with the date of the check.
What customers report
Results as the vendor or the customer published them, with the source and the date.
Questions about Gemini and OpenAI API
Which is used more, Gemini or OpenAI API?
OpenAI API has more customers on usedby: 5 against 2 for Gemini.
Do companies use both Gemini and OpenAI API?
usedby has not found a company with a confirmed or observed line on both Gemini and OpenAI API yet.
Who uses Gemini?
2 companies on usedby, each with the public page that shows it. See who uses Gemini.
Who uses OpenAI API?
5 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 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.