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DeepSeek V4
1M Context, AI Assistant New Era

Experience DeepSeek V4, China's open-source AI flagship. 1M token context, leading Agent capabilities, reasoning performance on par with top closed-source models. Free to use now at chat.deepseek.com.

What is DeepSeek V4

DeepSeek V4 is the latest generation large language model from China's open-source AI leader DeepSeek. With 1M token context window, it leads in Agent capabilities, world knowledge, and reasoning performance among domestic and open-source models.

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One-Line Definition

DeepSeek V4 is an AI assistant that understands Chinese better than GPT and has longer context than Claude - completely free to use.

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Ultra-Long Context

1M token context window - process entire books, codebases, or hundreds of pages in one go.

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Completely Free

Free to use at chat.deepseek.com with generous API free tier - excellent cost performance.

Why DeepSeek V4

Five core reasons to choose DeepSeek V4

1️⃣

1M Context, Industry Leading

Traditional AI models have context limits of just tens of thousands of tokens. DeepSeek V4 breaks this bottleneck with 1M token context - let AI read entire books, codebases, or analyze hundreds of pages at once.

2️⃣

Massive Agent Capability Upgrade

DeepSeek V4 is specially optimized for Claude Code, OpenClaw, OpenCode and other major Agent products. In Agentic Coding benchmarks, V4 achieves the best among current open-source models, outperforming Sonnet 4.5 and approaching Opus 4.6 non-thinking mode quality.

3️⃣

World-Class Reasoning Performance

In math, STEM, and competitive coding reasoning tasks, DeepSeek V4 surpasses all publicly evaluated open-source models, achieving results on par with GPT-4, Claude, and other top closed-source models.

4️⃣

Affordable API Service

DeepSeek V4 offers Pro and Flash versions. Flash is smaller, faster, and cheaper; Pro is more powerful for complex reasoning and deep analysis.

5️⃣

Fully Open Source, Transparent

DeepSeek V4 model weights are open source on HuggingFace and ModelScope with publicly available technical reports. Committed to long-termism - not seduced by praise, not frightened by criticism.

How to Use DeepSeek V4

Two easy ways to start using DeepSeek V4

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Method 1: Official Website (Recommended for Beginners)

1. Open browser, visit chat.deepseek.com
2. Register or login (supports phone, WeChat)
3. Select DeepSeek V4 model, start chatting
4. Enjoy the power of 1M ultra-long context

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Method 2: API Call (For Developers)

DeepSeek V4 API is fully compatible with OpenAI format - just change the model parameter:

model = "deepseek-v4-pro" (Pro version, more powerful)
model = "deepseek-v4-flash" (Flash version, faster and cheaper)

Both versions support thinking mode - set reasoning_effort to adjust thinking intensity.

Features

DeepSeek V4 provides comprehensive AI capabilities

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Ultra-Long Context Processing

1M token context window - process entire books in one input, cross-document analysis, DSA sparse attention mechanism for efficiency.

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Agentic Coding

Full support for code writing, debugging, and optimization. Compatible with Claude Code, OpenClaw, OpenCode. Global understanding of complex projects.

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Multimodal Reasoning

Accurate math problem solving, STEM analysis, competition-level code generation, logical reasoning and common sense judgment.

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Thinking Mode

User-controllable thinking intensity. Step-by-step reasoning for complex problems. Self-reflection and self-correction. Transparent and interpretable thinking process.

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API Compatible

100% compatible with OpenAI ChatCompletions API, supports Anthropic format. Easy migration from existing projects. Complete official documentation.

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Optimized for Chinese

Deeply optimized Chinese understanding and generation. Excellent performance in Chinese context. Understands Chinese internet culture better than GPT.

Use Cases

DeepSeek V4 is suitable for various practical applications

📄 Long Document Analysis

Feed entire product manuals, bidding documents, or legal contracts to DeepSeek V4. It extracts key points, identifies risks, and summarizes. 1M context enables precise "needle in haystack" information retrieval.

💻 Codebase Understanding

When newcomers take over legacy codebases, it often takes weeks to understand them. DeepSeek V4 can read entire repositories at once, quickly generate architecture diagrams, identify core logic, and explain function purposes - dramatically shortening onboarding time.

📚 Academic Research Assistant

When reading papers, DeepSeek V4 can process dozens of papers simultaneously, helping you discover research trends, identify gaps, and compare different viewpoints across papers.

✍️ Content Creation Assistant

When writing novels, series articles, or complete reports, DeepSeek V4 remembers all previous details, maintaining narrative consistency and avoiding the "amnesia" problem common in AI writing.

🔄 Agent Workflow Automation

DeepSeek V4's powerful Agent capabilities make it the best partner for automated workflows. Combined with Claude Code or OpenClaw, it can achieve complex automation tasks like automatic data analysis, report generation, and code review.

FAQ

Common questions about DeepSeek V4

Is DeepSeek V4 free?
Yes, DeepSeek V4 is free to use at chat.deepseek.com. API also offers a free tier, with affordable pay-as-you-go pricing beyond that.
Which is better, DeepSeek V4 or GPT-4?
In ultra-long context processing, DeepSeek V4's 1M token far exceeds GPT-4's limits. In reasoning performance, DeepSeek V4 reaches the level of top closed-source models. In Chinese processing, DeepSeek V4 has a natural advantage.
How to choose between Flash and Pro?
For simple tasks (daily Q&A, text polishing), Flash is recommended - fast and low cost. For complex tasks (code development, deep analysis, long writing), Pro is recommended - more powerful.
Can DeepSeek V4 really reach 1M context?
Yes, DeepSeek V4's maximum context is 1M token, approximately 1M Chinese characters or 6M English characters. This is achieved through a new attention mechanism and DSA sparse attention - globally leading context capability.
How to migrate from old API?
Change model parameter from deepseek-chat to deepseek-v4-flash (non-thinking mode), or deepseek-reasoner to deepseek-v4-pro (thinking mode). base_url remains unchanged. Note: Old API will be deprecated on July 24, 2026.
What usage methods does DeepSeek V4 support?
Three methods: 1) Official website online chat; 2) Official App (mobile); 3) API calls (supports OpenAI and Anthropic formats).

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