DeepSeek open-sources DeepInfer, the inference engine behind V4.1 Flash, under Apache 2.0

The repo ships the engine with DeepSeek's kernels (FlashMLA, DeepGEMM, DeepEP and others), several ways to split work across chips, draft-token decoding, structured outputs (regex, JSON schema or EBNF grammar) and two settings I haven't seen documented this plainly before: batch-invariant inference and deterministic sampling. The only supported model is DeepSeek-V4.1-Flash, and the default checkpoint is V4.1-Flash-1017.

It is not a full serving stack. DeepSeek says the KV cache system, prefill/decode disaggregation and load balancing across replicas are tied to its internal infrastructure and aren't in this release.

DeepSeek also released deepseek-recipe (MIT), which converts between common LLM API formats and model tokens the same way the official DeepSeek API does. Its deployment doc says one cluster serves 155 trillion tokens a day and earns $38 per GPU-hour at off-peak prices. Those are DeepSeek's numbers.