Pyyan / Language Models / o3 / o4-mini

o3 / o4-mini

The o-series reasoning line, retired Feb 2026.

retiredOpenAI ↗Verified 2026-08-13

Retired

Feb 2026

Specifications

Licence	Proprietary

Official links

OpenAI official site

What matters

Reasoning is now an effort setting on GPT-5.x, not a separate model

Best for nothing — migrate.

Compare with

All 5 side by side →

o3 / o4-mini vs Claude Fable 5 →o3 / o4-mini vs Claude Opus 5 →o3 / o4-mini vs GPT-5.6 Sol →o3 / o4-mini vs Gemini 3.1 Pro →o3 / o4-mini vs Claude Sonnet 5 →

Also in Language Models

Claude Fable 5 · Anthropic Claude Opus 5 · Anthropic GPT-5.6 Sol · OpenAI Gemini 3.1 Pro · Google Claude Sonnet 5 · Anthropic