Comprehensive side-by-side LLM comparison
. Both models have their strengths depending on your specific coding needs.
OpenAI
GPT-5 Codex, released by OpenAI in August 2025, is a coding-specialized large language model from the GPT-5 family engineered for software engineering, code generation, and agentic development workflows. It builds on GPT-5's architecture with optimizations targeting multi-file code editing, test generation, and automated debugging. GPT-5 Codex targets developers and agentic coding tools requiring a model tuned specifically for programming tasks.
OpenAI
OpenAI o3 mini, released by OpenAI in January 2025, is a compact reasoning model from the o3 family designed for efficient, cost-effective STEM problem-solving. It features a 200K token context window and adjustable chain-of-thought effort settings, allowing developers to trade reasoning depth for speed. o3 mini targets science, mathematics, and coding applications where lower inference cost and faster response times are a priority.
6 months newer

o3 mini
OpenAI
2025-01-31

GPT-5 Codex
OpenAI
2025-08
Context window and performance specifications
Available providers and their performance metrics
GPT-5 Codex
o3 mini
OpenAI
GPT-5 Codex
o3 mini
GPT-5 Codex
o3 mini