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What DeepSeek V4-Pro can do and why the price matters
DeepSeek V4-Pro is no lightweight model. It's a full-fledged Mixture-of-Experts model with 1.6 trillion total parameters and 49 billion active parameters — an architecture that activates only the relevant part of the neural network for each query, keeping it fast despite its enormous size. The model was released on April 24, 2026 as open-source — the weights are freely downloadable from HuggingFace.
Key capabilities include one million tokens of context (roughly 750,000 words — about the entire Lord of the Rings trilogy at once), native support for thinking mode, tool calling, and JSON output. The model is available through both OpenAI-compatible API and Anthropic API format, making migration from existing solutions trivial.
How does it stack up against the competition? The price comparison speaks volumes
Let's look at the hard numbers. All prices are per million tokens:
- DeepSeek V4-Pro: input $0.435 / output $0.87 (with 75% discount)
- GPT-5.5 (OpenAI): input $5.00 / output $30.00
- Claude Opus 4.7 (Anthropic): input $5.00 / output $25.00
- Claude Sonnet 4.6 (Anthropic): input $3.00 / output $15.00
- GPT-5.4 mini (OpenAI): input $0.75 / output $4.50
The result is clear: DeepSeek V4-Pro is 11.5× cheaper on input and 34.5× cheaper on output than GPT-5.5. Even against the "cheap" GPT-5.4 mini, V4-Pro is 42% cheaper on input and 81% cheaper on output. And yet in most benchmarks — particularly in agentic coding, mathematics, and STEM tasks — DeepSeek V4-Pro achieves results comparable to top closed-source models. In the open-source category, it has no competition.
Speed first: DeepSeek V4-Flash for pocket change
Alongside the Pro discount, DeepSeek is also highlighting its smaller model V4-Flash — 284 billion total parameters, 13 billion active. This one is even significantly cheaper: input at $0.14 and output at $0.28 per million tokens (cache miss). Flash is intended for simpler tasks where you don't need the full power of the Pro version but want fast response times.
For Czech developers and startups, this means one thing: for the price of one GPT-5.5 query, you can run 35 queries on DeepSeek V4-Pro. This fundamentally changes the economics of running AI applications — from chatbots to analytics tools to agentic systems.
Why is DeepSeek doing this? Strategy or price war?
DeepSeek's official reasoning is simple: they want developers to "bring innovative ideas to life." The reality, however, is likely more complex. The Chinese lab is betting on an aggressive pricing strategy to win the developer community over to its side — similar to what it did in the past with the DeepSeek-R1 model, which shocked the world with its performance at a fraction of the price.
Moreover, DeepSeek V4-Pro is open-source — anyone can download the weights and run the model on their own infrastructure free of charge. The API is "just" a convenient alternative for those who don't want to deal with hardware. This fundamentally sets DeepSeek apart from OpenAI or Anthropic, whose models are closed and available only through paid APIs.
What does this mean for Czech companies and developers?
The DeepSeek API is available globally, including in the Czech Republic. Payments can be made by credit card with billing in US dollars. The model supports Czech at a very good level — thanks to its massive 1M token context, it can handle even extensive Czech documents without issues. Direct invoicing in Czech crowns and Czech-language support, however, are not available.
From the perspective of the EU AI Act, the situation is interesting: DeepSeek as a Chinese company does not fall directly under European jurisdiction, but European companies using its API must fulfill their own obligations under the AI Act — especially if they deploy the model in regulated industries. Moreover, the open-source nature of the model opens up the possibility of running V4-Pro on European servers, which may be crucial for some companies from a data sovereignty standpoint.
The prices are staying — what's next?
DeepSeek's decision to make the discount permanent comes at a time when the AI model market is undergoing dramatic change. OpenAI is raising prices — GPT-5.5 costs $5/$30, double the previous generation. Anthropic is keeping Opus prices at the same level. Google is pushing Gemini models with aggressive pricing. And DeepSeek? They're going all-in on the "best price/performance ratio" card.
For developers, this is good news. Competition works — and when a Chinese open-source model can deliver performance comparable to GPT-5.5 at an 11× lower price, it pushes the entire market toward better pricing for everyone.
Is DeepSeek V4-Pro truly comparable to GPT-5.5?
In DeepSeek's official benchmarks, V4-Pro achieves comparable results in mathematics, STEM tasks, and agentic coding. In the world knowledge test (MMLU-Pro), it leads among open-source models, and in agentic coding (SWE-bench), it holds the open-source SOTA. For everyday tasks, the difference between V4-Pro and GPT-5.5 is minimal — GPT-5.5 has the edge more in niche creative scenarios and specialized domains.
Can I use DeepSeek V4-Pro for free?
Yes, via the chat at chat.deepseek.com in Expert Mode (V4-Pro) or Instant Mode (V4-Flash). The API, however, is paid according to the listed rates. If you want to run the model completely free of charge, you can download the open-source weights from HuggingFace and run it on your own hardware — but expect that you'll need powerful GPUs.
Does DeepSeek V4-Pro support Czech?
Yes, DeepSeek V4-Pro understands Czech and generates text in Czech at a very good level. The official documentation and interface, however, are not in Czech — everything is in English and Chinese. For production deployment in Czech, the model is fully usable.
