Comprehensive side-by-side LLM comparison
o4 mini supports multimodal inputs. Both models have their strengths depending on your specific coding needs.
OpenAI
GPT-5.3 Codex, released by OpenAI in February 2026, is a coding-specialized large language model from the GPT-5.3 family. It targets software engineering workflows including automated code generation, test writing, and agentic multi-file editing, built on the incremental improvements of the GPT-5.3 generation.
OpenAI
OpenAI o4 mini, released by OpenAI in April 2025, is a compact reasoning model from the o4 family that combines multimodal understanding with efficient chain-of-thought processing. It features a 200K token context window and native image understanding, with strong performance on mathematics and coding benchmarks relative to its inference cost. o4 mini targets cost-sensitive applications requiring both visual reasoning and mathematical accuracy.
9 months newer

o4 mini
OpenAI
2025-04-16

GPT-5.3 Codex
OpenAI
2026-02
Context window and performance specifications
Available providers and their performance metrics
GPT-5.3 Codex
o4 mini
OpenAI
GPT-5.3 Codex
o4 mini
GPT-5.3 Codex
o4 mini