The deciding difference is operational: Ollama can run on infrastructure you control, OpenAI cannot. If that constraint is real for you, it settles the choice before anything else is considered.
GPT and o-series via the Responses API.
Open-weight models on your own machine. Nothing leaves the box.
| OpenAI | Ollama | |
|---|---|---|
| Licence | Proprietary | Open source |
| Pricing | usage based | open source |
| Self-hostable | No | Yes |
| Languages | TypeScript, Python | TypeScript, Python |
| Install | npm install openai | brew install ollama |
| Keys required | OPENAI_API_KEY | None |
The deciding difference is operational: Ollama can run on infrastructure you control, OpenAI cannot. If that constraint is real for you, it settles the choice before anything else is considered. OpenAI: GPT and o-series via the Responses API. Ollama: Open-weight models on your own machine. Nothing leaves the box.
OpenAI is a hosted service only. Ollama can run on your own infrastructure.
OpenAI is proprietary (usage based). Ollama is open source (open source).
Every page here answers to Accept: text/markdown and returns the same content at roughly a tenth the tokens. No separate site, no toggle — same URL.
curl -s -H "Accept: text/markdown" https://newagent.build/compare/openai-vs-ollama