DeepSeek-V4 preview undercuts rivals ~10x; legacy API names deprecate July 24

DeepSeek-V4's preview is a pricing shock. The lineup pairs V4-Pro (1.6T parameters, 49B activated) with V4-Flash (284B parameters, 13B activated), both offering a 1-million-token context window enabled by DSA sparse attention. The number that matters: V4-Flash at $0.28 per million output tokens, roughly 10x cheaper than Western frontier models — and by some comparisons ~97% cheaper than GPT-5.5.

Operationally, DeepSeek is standardizing the 1M-token context across its lineup and introducing peak/off-peak API pricing (charging double during peak hours) to manage load — a novel way to shape demand. Legacy model names deepseek-chat and deepseek-reasoner deprecate July 24, forcing a migration, with the full V4 launch expected mid-July.

The developer reaction was intense. r/DeepSeek threads like 'Switched to Open Code. DeepSeek v4 flash is the king' (155 upvotes) and questions about wiring V4 into Claude Code and VS Code signal real adoption momentum among cost-sensitive builders. The debate: whether the pricing is structurally sustainable or a tactical loss-leader to grab share.

Competitive context: V4 is the leading edge of a broader Chinese cost assault (see GLM-5.2 trained for ~$25M on Huawei silicon) that is squeezing Western labs' pricing power — pressure Anthropic's $2/M Sonnet 5 and OpenAI must now answer. Caveats: cheap output pricing doesn't capture quality gaps, and geopolitical/security concerns (echoed by Alibaba's Claude Code ban and warnings about Chinese-model code bias) complicate enterprise adoption. What to watch: independent coding benchmarks and whether V4 pricing holds after GA.