# Gemini vs OpenAI API: who uses which

On usedby, 2 companies use Gemini and 5 use OpenAI API. No company is listed with both yet. Counts include every proof level, job-post signals included. Companies named on both have a confirmed or observed line on each side. Latest check 2026-10-07: 6 of 7 public lines checked.

## Side by side

|  | [Gemini](https://www.usedby.ai/tools/gemini.md) | [OpenAI API](https://www.usedby.ai/tools/openai-api.md) |
|---|---|---|
| Public customers | 2 | 5 |
| Confirmed | 0 | 3 |
| Observed | 0 | 1 |
| Signals (job posts) | 2 | 1 |
| Top industries of customers | Data & Analytics (2) | Biotech & Pharma (1), DevTools & Infrastructure (1), Marketing Tech (1) |
| Category | Foundation Models (LLMs) | Foundation Models (LLMs) |

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Source: https://www.usedby.ai/compare/gemini-vs-openai-api · How we check: https://www.usedby.ai/methodology