OpenAI API vs Together AI: who uses which
Customers, public proof and the companies that use both.
On usedby, 5 companies use OpenAI API and 33 use Together AI. 1 company uses both, including Cursor. Together AI leads among the Artificial Intelligence companies on usedby that use either tool.Latest check Oct 14, 2026: 37 of 38 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 OpenAI API, Together AI, or both
Every company with a public proof for at least one of the two tools.
4
use only OpenAI API
1
company uses both
32
use only Together AI
4 companies use only OpenAI API, 32 use only Together AI and 1 uses both, out of the 37 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 | First public proof, Together AI |
|---|---|---|
 Cursor | On or before Oct 2026 | On or before Apr 2026 |
Side by side
Facts from our data and from each vendor's public pages. Each line says where it comes from.
OpenAI API
Together AIWhat customers report
Results as the vendor or the customer published them, with the source and the date.
OpenAI API
No reviewed story for OpenAI API yet.
Together AI
Time to First Token (TTFT): Improved by up to 95%
Arcee AI
Vendor case study, together.ai, captured Oct 9, 2026
Questions about OpenAI API and Together AI
Which is used more, OpenAI API or Together AI?
Together AI has more customers on usedby: 33 against 5 for OpenAI API.
Do companies use both OpenAI API and Together AI?
Yes. 1 company uses both on usedby, including Cursor.
Who uses OpenAI API?
5 companies on usedby, each with the public page that shows it. See who uses OpenAI API.
Who uses Together AI?
33 companies on usedby, each with the public page that shows it. See who uses Together AI.
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.