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 o1 mini, released by OpenAI in September 2024, is a lightweight reasoning model from the o1 family optimized for efficient STEM problem-solving at lower cost and latency. It features a 128K token context window and applies chain-of-thought reasoning specifically tuned for mathematics, science, and coding tasks. o1 mini targets use cases where rapid, cost-efficient reasoning is preferred over the broader capabilities of the full o1 model.
10 months newer

o1 mini
OpenAI
2024-09-12

GPT-5 Codex
OpenAI
2025-08
Context window and performance specifications
Available providers and their performance metrics
GPT-5 Codex
o1 mini
OpenAI
GPT-5 Codex
o1 mini
GPT-5 Codex
o1 mini