Free DeepSeek V4 Is Now Available on Felo Search — Try It Free
Felo Search adds day-one support for DeepSeek V4, the open-source model rivaling GPT-5.4 and Claude Opus. Try DeepSeek V4-Pro and V4-Flash for free on Felo.
DeepSeek just released V4. A trillion-parameter open-source model that matches GPT-5.4 and Claude Opus 4.6 on most benchmarks, shipped today under an MIT license.
You can already use it on Felo Search. No API key, no setup, no paywall. Pick the model, ask a question, done.
What Is DeepSeek V4?
DeepSeek V4 comes from the Hangzhou-based AI lab behind last year's V3. The V4 series has two variants:
DeepSeek V4-Pro — the flagship. 1.6 trillion total parameters with 49 billion active per query, trained on over 32 trillion tokens. It's built for complex reasoning, coding, and research tasks that demand frontier-level intelligence.
DeepSeek V4-Flash — the lightweight sibling. 284 billion total parameters, 13 billion active. Designed for speed and everyday tasks where you need a fast, capable answer without the overhead.
Both models share a one-million-token context window — long enough to process entire codebases, research papers, or book-length documents in a single pass.
Why the million-token context matters
Context window size determines how much information a model can consider at once. Most models top out at 128K or 200K tokens. A million tokens is roughly 750,000 words — about 10 full-length novels, or a mid-sized company's entire internal documentation.
In practice, this means you can feed V4 an entire GitHub repository and ask it to find a bug. You can upload a 300-page legal filing and ask for a summary of every clause that mentions liability. You can paste in a semester's worth of lecture notes and ask it to connect themes across weeks of material.
Previous models would force you to chunk that work — split documents, summarize pieces, then stitch answers together. V4 handles it in one shot.
The numbers that matter
DeepSeek published benchmark results that put V4-Pro in direct competition with the most capable closed models:
V4-Pro-Max — the extended reasoning mode — scored 93.5% on LiveCodeBench and 89.8% on IMOAnswerBench, outperforming several closed-source competitors on math and competitive programming.
This is an open-source model performing at the frontier. Not close to it — at it.
What makes V4 different
Three architectural changes set V4 apart:
Hybrid attention architecture. V4 combines Compressed Sparse Attention (CSA) with Heavily Compressed Attention (HCA). V4-Pro uses only 27% of the compute and 10% of the memory that V3 needed for million-token contexts. That's not a minor tweak — it's why the model can actually handle a million tokens in practice, not just on paper.
Engram conditional memory. A memory system that lets the model selectively recall information across long contexts. In plain terms: it can work through a 500-page document without losing track of what it read on page 12.
Three reasoning modes. Non-Think gives you fast, direct answers. Think High walks through problems step by step. Think Max throws maximum compute at the hardest questions — proofs, competitive programming, multi-step research. You pick the depth.
Why Felo Search Added DeepSeek V4 on Day One
Felo Search is built around one idea: give people the best AI models for answering questions, without making them manage APIs or subscriptions.
Adding DeepSeek V4 on launch day fits that. Here's why it matters:
Different questions need different models. A quick factual lookup doesn't need the same horsepower as debugging a complex algorithm or analyzing a legal contract. With V4-Pro and V4-Flash now available alongside other leading models, you can match the model to the task.
DeepSeek V4 is MIT-licensed and open-weight. Felo passes that accessibility forward — you can use both V4-Pro and V4-Flash on Felo Search for free. No token limits, no credit card required.
DeepSeek V4 was trained with heavy emphasis on multilingual data, which aligns with Felo's core strength in cross-language search. Whether you're searching in English, Chinese, Japanese, or any other language, V4 delivers strong results.
How to Use DeepSeek V4 on Felo Search
Getting started takes about 10 seconds:
Step 1: Open Felo Search.
Head to felo.ai in your browser. No account required — though signing up unlocks additional features.
Step 2: Select the DeepSeek V4 model.
Look for the model selector in the search interface. You'll see DeepSeek V4-Pro and V4-Flash listed alongside other available models. Pick the one that fits your needs:
- Choose V4-Pro for complex research, coding questions, detailed analysis, or anything that benefits from deep reasoning.
- Choose V4-Flash for quick answers, everyday questions, summaries, and tasks where speed matters more than maximum depth.
Step 3: Ask your question.
Type your query naturally. Felo combines DeepSeek V4's reasoning with real-time web search, so you get answers grounded in current information — not just what the model learned during training.
Step 4: Explore the results.
Felo presents V4's response with inline citations, so you can verify sources. You can follow up with additional questions, switch models mid-conversation, or export the results to a LiveDoc for further editing.
That's it. No API keys, no configuration, no billing setup.
When to Use V4-Pro vs. V4-Flash
Both models are capable, but they're optimized for different scenarios. Here's a practical guide:
V4-Pro is the right pick when you need:
- Deep research — analyzing academic papers, comparing technical specs, or pulling together information from multiple sources. V4-Pro's million-token context and reasoning modes handle complexity that lighter models can't.
- Code generation and debugging. With a Codeforces rating of 3,206 and 80.6% on SWE-bench, V4-Pro is one of the strongest coding models available, open-source or otherwise. Writing functions, reviewing pull requests, tracking down subtle bugs — it handles all of it.
- Math and scientific reasoning. V4-Pro-Max scored 89.8% on IMOAnswerBench. If your question involves proofs, derivations, or quantitative analysis, this is the one.
- Long-document analysis. Need to process a 200-page report or an entire codebase? The million-token context window means V4-Pro holds it all in memory at once.
V4-Flash works better when you need:
- Quick answers. Factual lookups, definitions, brief explanations — V4-Flash responds faster and handles these just as well.
- Everyday productivity. Drafting emails, summarizing articles, brainstorming, translating text. V4-Flash is more than capable for daily work.
- High-volume queries. If you're running through a lot of questions in a session, V4-Flash keeps things moving without sacrificing quality on routine tasks.
DeepSeek V4 vs. other models
The AI model landscape in 2026 is crowded. Here's where V4 actually lands:
vs. GPT-5.4: V4-Pro trails by a narrow margin on most benchmarks, roughly 1-2 percentage points. But it leads on competitive programming (Codeforces) and matches or beats GPT-5.4 on several coding tasks. For most real-world use, the difference is hard to notice. And V4 is open-source — GPT-5.4 is not.
vs. Claude Opus 4.6: V4-Pro outperforms Opus 4.6 on MMLU, MATH, and Codeforces. Claude still has an edge in nuanced writing and instruction-following, but for raw reasoning and coding, V4-Pro pulls ahead.
vs. Gemini 3.1 Pro: V4-Pro falls slightly behind on world knowledge benchmarks but leads on code and math. Both share million-token context capabilities.
The real differentiator is the license. GPT-5.4, Claude, and Gemini are all closed. DeepSeek V4 ships under MIT with full weights on Hugging Face. Researchers, developers, and companies can inspect, fine-tune, and deploy it without restrictions. On Felo, that translates to frontier-level AI at no cost to you.
What this means for Felo users
Adding DeepSeek V4 isn't just about having another model option. It reflects a shift in how AI search works:
No single model dominates every task. By offering DeepSeek V4 alongside other leading models, Felo lets you experiment and find what works best for your specific questions.
Open-source models have caught up. A year ago, open-source models were clearly a tier below the best closed models. DeepSeek V4 closes that gap almost entirely. You no longer have to choose between quality and accessibility.
Free access removes friction. DeepSeek V4-Pro via API costs $1.74 per million input tokens. V4-Flash costs $0.14. On Felo, both are free. That removes the barrier between you and the most capable AI tools available today.
Frequently asked questions
Is DeepSeek V4 really free on Felo?
Yes. Both V4-Pro and V4-Flash are available at no cost on Felo Search. You don't need to create an account to start, though signing up gives you access to features like conversation history and LiveDoc export.
What's the difference between V4-Pro and V4-Flash?
V4-Pro is the larger model (1.6T parameters, 49B active) built for complex tasks — research, coding, math, long-document analysis. V4-Flash is smaller (284B parameters, 13B active) and faster, better suited for quick lookups and everyday questions. Both share the same million-token context window.
Can I use DeepSeek V4 in languages other than English?
Absolutely. DeepSeek V4 was trained on multilingual data and performs well across English, Chinese, Japanese, Korean, and many other languages. Combined with Felo's cross-language search capabilities, you can ask questions in one language and get answers that draw from sources in others.
How does Felo Search combine DeepSeek V4 with web search?
When you ask a question on Felo, the platform searches the web in real time and feeds relevant, current information to the model alongside your query. This means V4's answers are grounded in up-to-date sources, not limited to its training data. Every response includes inline citations so you can verify the information yourself.
Is DeepSeek V4 open-source?
Yes. Both V4-Pro and V4-Flash are released under the MIT license with full weights available on Hugging Face. Anyone can download, inspect, fine-tune, or deploy them.
Start using DeepSeek V4 on Felo now
DeepSeek V4 is live on Felo Search as of today. Whether you're a developer debugging code, a researcher digging through papers, a student working through problem sets, or just someone who wants better answers to hard questions — V4 is ready.
Pick a model. Ask a question. See what a trillion-parameter open-source model can do.