Comprehensive side-by-side LLM comparison
. Both models have their strengths depending on your specific coding needs.
OpenAI
GPT-5.2 Codex is a coding-specialized variant from the GPT-5.2 family, designed for software engineering workflows including automated code generation, multi-file editing, and agentic development. It builds on GPT-5.2's improved instruction following and long-context capabilities, with optimizations specifically targeting programming tasks and agentic software workflows.
OpenAI
GPT-OSS-120B, released by OpenAI in August 2025, is an open-weight large language model with 120 billion parameters distributed under the Apache 2.0 license. It represents OpenAI's entry into the open-source model space, enabling developers to self-host and fine-tune a GPT-5-generation-class model. GPT-OSS-120B targets research applications, on-premises deployments, and custom fine-tuning workflows requiring a large open-weight base model.
5 months newer

GPT-OSS-120B
OpenAI
2025-08

GPT-5.2 Codex
OpenAI
2026-01-14
Context window and performance specifications
Available providers and their performance metrics
GPT-5.2 Codex
GPT-OSS-120B
Hugging Face
GPT-5.2 Codex
GPT-OSS-120B
GPT-5.2 Codex
GPT-OSS-120B