Gemini 3.1 Flash and GPT-5-Codex-Mini don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. GPT-5-Codex-Mini shipped 111 days before Gemini 3.1 Flash, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

Direct benchmark comparisons are unavailable — Gemini 3.1 Flash and GPT-5-Codex-Mini don't publish scores on any of the same benchmarks.