| OpenAI API | Claude API | DeepSeek API | Gemini API | |
|---|---|---|---|---|
| Cheapest model | GPT-5 Nano $0.05/$0.40 | Haiku 4.5 $1/$5 | V3.2 $0.28/$0.42 | Flash 2.0 Free tier |
| Flagship price | GPT-5.2 $1.75/$14 | Opus 4.6 $5/$25 | V3.2 $0.28/$0.42 | 2.5 Pro $1.25/$10 |
| Context window | Up to 1M (GPT-4.1) | 200K | 128K | 1M |
| Writing quality | Good | Best in class | Good | Good |
| Image generation | GPT Image API | Not available | Not available | Imagen API |
| Voice/Audio | Realtime API, Whisper, TTS | Not available | Not available | Gemini Live |
| Open source | Yes (MIT) | Gemma (partial) | ||
| Fine tuning | GPT-4.1, GPT-4o, o4-mini | Not available | Not available | Gemini models |
Choosing your API provider
OpenAI API is the safest default: broadest capabilities, most mature ecosystem, and the largest third party tooling community. Choose Claude API if writing quality, nuanced reasoning, and coding are your priority. Choose DeepSeek if cost is the primary driver. Choose Gemini if you are already in the Google Cloud ecosystem.