DeepSeek-V4 Preview: Entering the Era of Affordable Million-Token Context
Today, the preview version of our new series model DeepSeek-V4 is officially launched and open-sourced simultaneously.DeepSeek-V4 features an ultra-long context of one million tokens, achieving leading performance in Agent capabilities, world knowledge, and reasoning among domestic and open-source models. The model comes in two sizes:Starting today, visit the official website chat.deepseek.com or the official App to converse with the latest DeepSeek-V4 and explore the new experience of 1M ultra-long context memory. The API service has also been updated — simply change model_name to deepseek-v4-pro or deepseek-v4-flash to call it.DeepSeek-V4-Pro: Performance rivaling top closed-source modelsSignificantly improved Agent capabilities: Compared to previous generations, DeepSeek-V4-Pro's Agent capabilities have been markedly enhanced. In Agentic Coding evaluations, V4-Pro has achieved the best level among current open-source models, and also performs excellently in other Agent-related evaluations. Currently, DeepSeek-V4 has become the Agentic Coding model used internally by company employees. According to evaluation feedback, the user experience is better than Sonnet 4.5, and delivery quality is close to Opus 4.6 non‑thinking mode, though there is still a certain gap compared to Opus 4.6 thinking mode.Rich world knowledge: In world knowledge evaluations, DeepSeek-V4-Pro significantly outperforms other open-source models, falling only slightly behind the top closed-source model Gemini-Pro-3.1.World-class reasoning performance: In evaluations of mathematics, STEM, and competitive coding, DeepSeek-V4-Pro surpasses all currently published open-source models, achieving outstanding results comparable to the world's top closed-source models.DeepSeek-V4-Flash: A faster, more economical optionCompared to DeepSeek-V4-Pro, DeepSeek-V4-Flash has slightly less world knowledge, but demonstrates close reasoning capabilities. Due to its smaller parameter count and activation size, V4-Flash provides faster and more cost-effective API services.In Agent evaluations, DeepSeek-V4-Flash performs on par with DeepSeek-V4-Pro on simple tasks, but still lags behind on highly difficult tasks.Structural innovation and ultra-high context efficiencyDeepSeek-V4 introduces a brand‑new attention mechanism that compresses along the token dimension. Combined with DSA (DeepSeek Sparse Attention), it achieves world‑leading long‑context capabilities while significantly reducing compute and VRAM requirements compared to traditional methods. From now on, 1M (one million) tokens of context will be the standard for all official DeepSeek services.DeepSeek-V4 vs DeepSeek-V3.2: changes in computation and memory usage with context lengthSpecialized optimization for Agent capabilitiesDeepSeek-V4 has been adapted and optimized for mainstream Agent products such as Claude Code, OpenClaw, OpenCode, and CodeBuddy, showing improved performance in coding tasks, document generation, and more. The image below shows an example of a slide generated by V4-Pro using a certain Agent framework:(Swipe up/down or click to enlarge)API AccessThe DeepSeek API now supports both V4-Pro and V4-Flash, compatible with the OpenAI ChatCompletions interface and the Anthropic interface. To access the new models, keep the base_url unchanged and change the model parameter to deepseek-v4-pro or deepseek-v4-flash.Both V4-Pro and V4-Flash have a maximum context length of 1M, and support both non‑thinking mode and thinking mode. The thinking mode supports the reasoning_effort parameter to set thinking intensity (high/max). For complex Agent scenarios, it is recommended to use thinking mode with intensity set to max. Please refer to the API documentation for model invocation and parameter adjustment:https://api-docs.deepseek.com/guides/thinking_modePlease note: The two old API model names deepseek-chat and deepseek-reasoner will be deprecated after three months (2026-07-24). During the current transitional period, these two model names point to the non‑thinking mode and thinking mode of deepseek-v4-flash, respectively.Open‑source weights and local deploymentDeepSeek-V4 model open‑source links:https://huggingface.co/collections/deepseek-ai/deepseek-v4https://modelscope.cn/collections/deepseek-ai/DeepSeek-V4DeepSeek-V4 technical report:https://huggingface.co/deepseek-ai/DeepSeek-V4-Pro/blob/main/DeepSeek_V4.pdf
DeepSeek V4 Preview Launches Today: 1M Context Free as Standard, Agentic Coding Beats Sonnet 4.5
This morning (April 24), DeepSeek quietly dropped the V4 preview — simultaneous releases on the official website, App, API, and open source, without any prior notice.What they delivered is pretty aggressive:1M context free as standard – From today, 1 million tokens of context becomes the default configuration for all official DeepSeek services. No "long context add-on", no extra charge.Two versions: V4-Pro with 1.6T total parameters, 49B activated — the flagship; V4-Flash with 284B parameters, 13B activated — focused on speed and low cost.New DSA sparse attention mechanism (DeepSeek Sparse Attention) that compresses along the token dimension, significantly cutting compute and VRAM costs for long contexts.How's the performance? Quoting DeepSeek's official announcement: V4-Pro "outperforms Sonnet 4.5" in Agentic Coding benchmarks, with "delivery quality close to Opus 4.6 non‑thinking mode", and in world knowledge evaluation it is "only slightly behind Gemini-Pro-3.1". If this holds true, it would be the first time an open‑source model goes toe‑to‑toe with closed‑source flagships on the most valuable battleground — coding agents.We'll have to wait for independent benchmarks from the community to verify. But judging from the technical report, this is not a minor tweak to V3 — it's a structural overhaul.One more critical detail: The old API model names deepseek-chat and deepseek-reasoner will be deprecated in 3 months (July 24, 2026). Currently they point to the non‑thinking/thinking modes of V4-Flash. Developers who want to continue using them should change the model_name to deepseek-v4-pro or deepseek-v4-flash.Some personal thoughts – Around this time last year, people were still arguing whether DeepSeek's performance was just faked with data contamination. Less than a year later, the V4 preview makes 1M context free as standard and claims the top open‑source spot for Agentic Coding. They don't rely on PR stunts — they just ship the product, shutting up all the critics.The model is open‑sourced, and the technical report has been released as well. Now it's up to the community to run reproduction benchmarks.But this day will likely be another sleepless night for product managers at the big tech firms.