GPT-5.1 Codex vs Qwen2.5 14B Instruct

GPT-5.1 Codex

OpenAI

GPT-5.1 Codex, released by OpenAI in November 2025, is a coding-specialized model from the GPT-5.1 family engineered for software engineering tasks including code generation, multi-file editing, and agentic development. It targets developers and automated coding pipelines requiring a GPT-5.1-generation model tuned for programming.

Alibaba / Qwen

Qwen2.5-14B-Instruct is a 14-billion-parameter language model from Alibaba released in September 2024 within the Qwen2.5 family, occupying the mid-tier of the series between efficiency-focused small models and the high-capability 72B flagship. Trained on 18 trillion tokens with emphasis on instruction alignment, code understanding, and multilingual reasoning, it offers a strong performance-to-compute ratio for developers who need more capability than 7B but cannot serve 32B or larger models. The model supports 128K context windows and structured output generation out of the box.