Does Halcyon use OpenAI?
Yes
We hold strong evidence for this.
- The company names it in its own subprocessor list, a statement that this vendor handles its customers' data.
How we know
About Halcyon
Halcyon provides software for business valuations, insights, and next steps. It serves modern business advisors.
Summarized from its homepage on 10 Nov 2026.
What else Halcyon uses
Halcyon has evidence for 14 vendors. The strongest:
Amazon Web Services
Apideck
Box
Google Cloud
PostHog
Reducto
Sentry
Stripe
Vanta
Other companies using OpenAI
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- Every company and vendor, with its public source
- 100 API calls a month, plus MCP and the Chrome extension
- Work email only. No card, no sales call