GPT-4o
OpenAI previous-gen multimodal model — text, vision, audio
Verdict
Two generations back from GPT-5.6, and still widely deployed — the API is stable and a huge number of production RAG and agentic pipelines are built on it. JSON mode, function calling, and vision are battle-tested. Fine to keep running if it is already tuned and evaluated; start new projects on GPT-5.6 instead.
Other Text Generation & Reasoning
- GPT-5.6Production
OpenAI current flagship — Sol/Terra/Luna tiers, 1.05M context
- GPT-5Superseded
OpenAI's previous flagship — superseded by GPT-5.6
- GPT-5 miniProduction
OpenAI's cost-efficient GPT-5-tier model — most of the quality at a fraction of the cost
- GPT-4o miniStable
OpenAI's previous-gen cost-efficient model — superseded by GPT-5 mini
- GPT-OSS 120BStable
OpenAI's first open-weight model — 120B params, fully downloadable
- Claude Fable 5Production
Anthropic's most intelligent generally available model — Mythos-class reasoning