DeepSeek-Math and GPT-5-Codex-Mini don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. DeepSeek-Math shipped 583 days before GPT-5-Codex-Mini, so benchmark comparisons should account for the intervening progress.

DeepSeek-Math is open weight, while GPT-5-Codex-Mini is proprietary.

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