The Engineering Behind the $0.28 Price Tag
DeepSeek-V4-Flash-0731 is a Mixture-of-Experts model with 284 billion total parameters but only 13 billion active per token [1], paired with hybrid compressed attention mechanisms that shrink the memory footprint of its 1 million token context window [1]. That combination - routing most computation away from the bulk of the model, then compressing the memory cost of long conversations - is why DeepSeek can charge $0.14 per million input tokens on a cache miss and just $0.28 per million output tokens [2], undercutting nearly every frontier lab on a per-token basis.
The real headline, though, is the cache-hit price: $0.0028 per million input tokens, a 98% discount versus the cache-miss rate [2]. That pricing structure is a tell - it's engineered around repeated agentic patterns, where a tool schema or system prompt gets reused thousands of times across a session, not around one-off chat queries. Reddit's technical threads trace the underlying trick to Multi-head Latent Attention compressing the KV cache, combined with reinforcement-learning post-training gains carried over since V3.2 - the same architectural lineage DeepSeek has iterated on since R1, refined enough that routine coding and agent tasks now cost fractions of a cent.




