DeepSeek in Claude Code (and the Engine They Gave Away)

DeepSeek open-sourced DeepInfer, the engine that runs its own API. Three days earlier it shipped V4.1-Flash-1017: MIT open weights, a 1M-token context, and $0.15 per million input tokens. A heavy day of AI coding costs about $2.10 with it, against $30 with Gemini 4 Argon. What you'll learn: → What DeepSeek released on 17 and 20 October, and why shipping the serving engine is rare → The model, honestly: DeepSeek's own benchmark gains, and where it sits against Claude Opus 5.5, Kimi K3.1 Pro and GPT-6.1 Terra → Inside DeepInfer: kernels, expert parallelism, DSpark speculative decoding and determ