DeepSeek retires legacy API endpoints, forcing migration to V4-Pro and V4-Flash

DeepSeek deprecated its legacy deepseek-chat and deepseek-reasoner API endpoints on July 24 at 15:59 UTC, forcing developers to migrate to the V4 family: V4-Pro (1.6 trillion parameters, 49B active) and V4-Flash (284B parameters, 13B active), both featuring a 1-million-token context window and a mixture-of-experts architecture. DeepSeek introduced peak/off-peak pricing, positioning V4-Pro output around $0.87 per million tokens during normal periods — dramatically undercutting comparable frontier models.

Early benchmarks suggest V4's performance is competitive with Anthropic's Opus models and GPT-5.6 Sol in coding tasks, and r/DeepSeek's 'Deepseek V4 Pro is AMAZING' thread (383 upvotes) reflected strong developer enthusiasm. But the abrupt endpoint deprecation frustrated developers over the short migration window.

The business backdrop is ambitious: DeepSeek is reportedly targeting a $71B valuation and a Shanghai STAR Market IPO filing by end of 2026. In a widely-discussed 4-hour investor meeting (r/LocalLLaMA, 803 upvotes), the founder said DeepSeek is prioritizing AGI over user growth and commercialization, and is likely to keep top models open-source.

Competitively, DeepSeek's aggressive pricing ($2/$6 vs $5/$25 comparables cited by developers) plus 1M-token context makes it a direct threat in the cost-sensitive tier where Anthropic's Sonnet and OpenAI's Terra compete. It also fuels the broader Chinese-open-model narrative rattling US tech stocks this week. Watch the IPO filing and whether V4 sustains its coding benchmark claims under independent testing.