Side-by-side technical and economic comparison between DeepSeek's DeepSeek-V3 (Legacy API Alias) and OpenAI's GPT-5.6 Mini.
• DeepSeek-V3 (Legacy API Alias): Classified as a Legacy Reference model (Legacy Reference (API Aliased)).
| Metric | DeepSeek-V3 (Legacy API Alias) | GPT-5.6 Mini | Advantage |
|---|---|---|---|
| Provider Organization | DeepSeek | OpenAI | — |
| Standard Input / 1M | $0.14 | $0.30 | DeepSeek-V3 (Legacy API Alias) (53% lower) |
| Cached Input / 1M | $0.014 | $0.03 | DeepSeek-V3 (Legacy API Alias) lower |
| Output / 1M | $0.28 | $1.20 | DeepSeek-V3 (Legacy API Alias) lower |
| Context Window | 128k | 400k | GPT-5.6 Mini (400k) |
| Max Generation Tokens | 8.2k | 16.4k | GPT-5.6 Mini |
| Tokenizer Family | DeepSeek Byte-level BPE (~128k vocabulary) | OpenAI o200k_base (200k vocabulary) | — |
Opt for DeepSeek-V3 (Legacy API Alias) when your engineering requirements prioritize DeepSeek's ecosystem, specific tokenizer efficiencies (Exact DeepSeek Tokenizer (±2%)), or when your expected prompt-to-completion ratios favor its $0.14/M input rate.
Opt for GPT-5.6 Mini when looking for OpenAI's tooling integration, specific context window depth (400k tokens), or when output generation volume favors its $1.2/M rate.