DeepSeek V4 Preview Release

DeepSeek's V4 Preview — open-sourced MoE models with 1M context standard, agentic-coding optimizations, and API pricing far below comparable closed models.

Links

• News post: https://api-docs.deepseek.com/news/news260424/
• Tech report: https://huggingface.co/deepseek-ai/DeepSeek-V4-Pro/blob/main/DeepSeek_V4.pdf
• Open weights: https://huggingface.co/collections/deepseek-ai/deepseek-v4
• API docs: https://api-docs.deepseek.com/
• Coverage / claims: r/Anthropic post by u/hibzy7 — "DeepSeek V4 Flash API is 18x cheaper on input, 28x cheaper on output, and matches Opus 4.8"
• Date: Released ~July 2026 (API live; legacy deepseek-chat/deepseek-reasoner retired Jul 24, 2026)

Overview

DeepSeek-V4 Preview is officially live and open-sourced, billed as "the era of cost-effective 1M context length." Two variants ship:

• DeepSeek-V4-Pro — 1.6T total / 49B active params. Performance rivaling the world's top closed-source models; open-source SOTA in agentic coding benchmarks, world-leading world knowledge (trailing only Gemini-3.1-Pro), and world-class reasoning (beats all current open models in Math/STEM/Coding).
• DeepSeek-V4-Flash — 284B total / 13B active params. Reasoning close to V4-Pro, on par on simple agent tasks, with smaller size, faster responses, and highly cost-effective API pricing.

The release is a major cost disruption: the V4 Flash API is ~18x cheaper on input and ~28x cheaper on output than comparable APIs (e.g. Opus 4.8) while matching Opus 4.8-level quality — verified against the official DeepSeek price sheet.

Structural Innovation & Context Efficiency

• Novel attention: Token-wise compression + DSA (DeepSeek Sparse Attention).
• Peak efficiency: World-leading long context with drastically reduced compute and memory cost.
• 1M standard: 1M context is the default across all official DeepSeek services.

Agent Capabilities

• DeepSeek-V4 is integrated with leading AI agents: Claude Code, OpenClaw, and OpenCode.
• Already driving DeepSeek's in-house agentic coding.

API Availability

• Keep base_url; just update the model to deepseek-v4-pro or deepseek-v4-flash.
• Supports both OpenAI ChatCompletions and Anthropic APIs.
• Both models support 1M context and dual modes (Thinking / Non-Thinking).
• ⚠️ deepseek-chat and deepseek-reasoner were fully retired after Jul 24, 2026, 15:59 UTC (previously routing to V4-Flash).

Significance

A major open-weights release that pairs frontier-ish quality with drastically lower API cost and native 1M context. Its explicit agent-tooling integrations (Claude Code, OpenClaw, OpenCode) and cost profile make it directly relevant to the loop-engineering and context-engineering practices documented elsewhere in this repo — cheap, long-context, agent-friendly models lower the token-cost barrier that Addy Osmani and Brittany Ellich flag as the main caveat of running loops.

Related

• moc-loop-engineering - Loop engineering; cheap long-context APIs make unattended loops more viable
• loop-engineering
• trq212-claude-5-context-engineering - Context engineering for Claude 5
• openclaw