Reviewed by Harsh Desai · Last reviewed:
DeepSeek
Open-source reasoning AI with frontier performance at 10x lower cost than ChatGPT
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DeepSeek is a Chinese AI lab that ships frontier-grade reasoning and coding models under a permissive MIT licence. The flagship V3.2 model competes head-to-head with GPT-5 and Claude Opus on maths, coding, and agentic benchmarks while charging roughly one tenth of the price for API access, and the full model weights are downloadable from GitHub for self-hosting. Free unlimited use is available through chat.deepseek.com on web, iOS, and Android.
What DeepSeek does:
- •DeepSeek V3.2 reasoning model a Mixture-of-Experts model with a 163K context window that won gold on the 2025 IMO and IOI maths and informatics olympiads. Toggle between fast "chat" mode and slow "reasoner" mode in one click.
- •DeepSeek Sparse Attention (DSA) the V3.2 architecture cuts compute by skipping low-relevance tokens during attention, which is how the API price stays at roughly $0.28 per million output tokens against GPT-5's $10.
- •Open-source weights on GitHub DeepSeek-V3 has 103,000+ stars and ships under MIT licence. You can download the model and run it on your own GPU cluster, fine-tune it, or deploy it via vLLM, SGLang, or Ollama.
- •Free web and mobile chat chat.deepseek.com gives unlimited messages with the V3.2 model and toggleable DeepThink reasoning mode at no cost. iOS and Android apps mirror the web experience.
- •Cheap API for builders the OpenAI-compatible API charges $0.14 per million input tokens (cache miss) and $0.28 per million output tokens, with cache hits dropping input to $0.0028 per million. That makes long-running agents and bulk classification jobs economically viable.
- •Strong code generation third-party reviewers report DeepSeek produces working code with fewer hallucinated libraries than GPT-5 on standard coding benchmarks, and the dedicated DeepSeek Coder V2 model is a specialised option for code tasks.
- •English and Chinese bilingual the model was trained on a Chinese-heavy corpus and excels at Mandarin tasks, but English performance is strong enough for everyday coding and reasoning. Multilingual evaluation leads many Western models.
- •Self-hostable for privacy because the weights are public, regulated industries (finance, healthcare, government) can run DeepSeek inside a private VPC with no data leaving the network.
- •Tool use and agentic workflows V3.2 was trained on a synthetic agentic-task pipeline, so it follows tool-call schemas and multi-step plans more reliably than V3.1 did.
- •OpenAI-compatible endpoint existing OpenAI client libraries (Python, Node, LangChain, LiteLLM) work without code changes by pointing the base URL at api.deepseek.com.
Pricing:
- •Free web and app chat $0/mo: unlimited messages on chat.deepseek.com, iOS, and Android. DeepThink reasoning mode is also free with no message cap published.
- •Pay-as-you-go cloud pay-as-you-go: $0.14 per million input tokens (cache miss), $0.0028 per million input tokens (cache hit), $0.28 per million output tokens. No monthly minimum.
- •Self-hosted $0 software cost: download the MIT-licensed weights from GitHub and run on your own GPU. Hardware cost depends on your deployment choice.
Limitations:
- •Data goes to China by default the hosted chat and API are operated from China and your prompts are subject to local data laws. For sensitive workloads use the open weights and self-host.
- •English creative writing lags GPT and Claude DeepSeek handles technical and reasoning prose well, but blog drafts and marketing copy in English are noticeably weaker than ChatGPT or Claude.
- •Censored on China-sensitive topics the hosted model declines to discuss Tiananmen, Taiwan independence, and similar topics. Self-hosted weights have looser guardrails after a small fine-tune.
Our Verdict
DeepSeek scores 7.5/10 because the price-to-performance ratio is unmatched in 2026: gold-medal maths reasoning and competitive coding output for roughly one tenth of what GPT-5 or Claude Opus charge, plus the full weights are MIT-licensed and self-hostable. The 163K context window, OpenAI-compatible API, and free unlimited web chat make it a serious option for cost-sensitive builders, technical teams in China, and any privacy-conscious org that needs to run frontier-grade reasoning behind their own firewall. The half-point gap to a 9 is mostly down to weaker English creative writing, China-routed default hosting, and content censorship on the hosted version.
For the Vibe Builder, DeepSeek is the obvious choice when your AI workflow is hammering an LLM thousands of times a day for classification, summarisation, or code generation and the bill is starting to hurt. Drop the OpenAI base URL to api.deepseek.com, keep your existing Python or Node client, and you cut costs by 90% overnight while keeping reasoning quality close to GPT-5 on most non-creative tasks. For consumer-facing chat where prose polish matters, pair it with ChatGPT or Claude as the writing layer.
For the Developer, this is the cheapest serious model on the market with a permissive licence and a real architectural innovation (Sparse Attention) under the hood. The 103,000+ GitHub stars on DeepSeek-V3, OpenAI-compatible endpoint, and active vLLM/SGLang/Ollama support mean you can prototype against the hosted API today and graduate to a self-hosted cluster tomorrow without rewriting client code. Tool calling and agentic task following improved meaningfully in V3.2.
Skip it if you mainly need polished English marketing copy or long-form blog drafts -- consider ChatGPT or Claude instead, both produce noticeably better prose. If your data cannot legally leave the EU or US and you cannot self-host (the hosted endpoint is China-based), try Claude or Gemini on a regional cloud. If you need a chat interface that will discuss any topic without a censorship layer, consider Grok or a self-hosted Llama variant.
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Frequently Asked Questions
How much does the DeepSeek API cost in 2026?
DeepSeek charges $0.14 per million input tokens on a cache miss, $0.0028 per million on a cache hit, and $0.28 per million output tokens for the V3.2 model. That is roughly 90% cheaper than GPT-5 and Claude Opus on equivalent tasks, with no monthly minimum. The web chat at chat.deepseek.com is free and unlimited.
DeepSeek vs ChatGPT: which should I pick?
Choose DeepSeek when cost matters more than prose polish: it matches GPT-5 on maths and coding benchmarks at one tenth the API price, ships with open weights, and is self-hostable. Choose ChatGPT when you need the best English creative writing, multimodal voice and image features, or your data cannot route through China. Both expose an OpenAI-compatible API.
Is DeepSeek really open-source?
Yes. The DeepSeek-V3 model weights are published on GitHub under the MIT licence with 103,000+ stars, and the V3.2-Exp variant is similarly available. You can download, fine-tune, or self-host the model commercially with no royalty. Run it locally with Ollama, or at scale with vLLM or SGLang.
Is my data safe with DeepSeek?
If you use chat.deepseek.com or api.deepseek.com, your prompts are processed in China and subject to local data laws -- treat that as the threat model. For sensitive or regulated workloads, download the open weights and self-host inside your own VPC; the model behaves identically and no data leaves your network.
What is DeepSeek V3.2 and how is it different from V3.1?
DeepSeek V3.2 is a reasoning-focused Mixture-of-Experts model released in late 2025 with a 163K context window. It introduces DeepSeek Sparse Attention, which skips low-relevance tokens to cut inference cost by roughly 50% versus V3.1-Terminus while preserving quality. V3.2 won gold on the 2025 IMO and IOI olympiads.
Is DeepSeek free?
Yes, DeepSeek offers a free version.
Who should use DeepSeek?
DeepSeek is built for vibe builders who want AI to handle the technical work and developers looking to accelerate their workflow. Common use cases include coding-assistant, reasoning-research, cheap-llm-api, self-hosted-llm, math-problem-solving.
What are the best alternatives to DeepSeek?
Popular alternatives to DeepSeek include Chatgpt, Claude, Gemini. Compare features and pricing in our Generalist AI directory to compare options.
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