DeepSeek vs ChatGPT: Complete Comparison 2026

What is DeepSeek

DeepSeek is a Chinese artificial intelligence startup founded by Liang Wenfeng, co-founder of the quantitative investment fund High-Flyer. Unlike OpenAI, which operates as a for-profit company under a mixed structure, DeepSeek was born with a radically different philosophy: develop frontier language models with a fraction of the training cost and publish them as open-source.

Its two most relevant models are DeepSeek-V3 and DeepSeek-R1. DeepSeek-V3 uses a Mixture-of-Experts architecture with 671 billion total parameters, of which only 37 billion are activated per query. This allows it to achieve competitive performance with GPT-4o consuming significantly fewer computational resources. Its training cost was approximately $5.5 million --compared to the estimated $100+ million for OpenAI models--.

DeepSeek-R1 is specifically designed for step-by-step reasoning: mathematics, logic and code. It explicitly shows its chain of thought, something that differentiates it from ChatGPT, where reasoning executes internally. The most recent version, DeepSeek-V3.2, unifies both capabilities: deep reasoning and tool use in a single model. But not everything is positive. The controversy over privacy and data storage on servers located in China has generated investigations by European regulators, including the block in Italy by the Garante.

Comparative Table: DeepSeek vs ChatGPT

These are the 10 criteria that really matter when comparing DeepSeek and ChatGPT in 2026:

The conclusion is clear: DeepSeek dominates in cost efficiency, mathematical reasoning and model transparency. ChatGPT wins in Spanish quality, plugin ecosystem, multimodal capabilities (vision, voice, image generation) and regulatory compliance options for companies. DeepSeek's API price is 6 to 25 times lower than OpenAI's, making it an extremely attractive option for projects with limited budget or high request volume.

Regarding reasoning, DeepSeek-R1 has demonstrated superior performance to GPT-4o in benchmarks like MATH-500 and AIME 2024. Its visible chain of thought approach allows auditing the model's logical process, something valuable in academic and scientific contexts where you need to verify the reasoning is correct --not just the final result--. DeepSeek-V3.2 has gone a step further: it obtained gold-level results at the International Mathematical Olympiad (IMO) and ICPC finals, positioning itself as the most powerful model in solving complex problems.

However, in tasks requiring nuanced understanding of Peninsular Spanish --idioms, formal registers, conversational tone--, ChatGPT remains clearly superior. GPT-4o has been trained with a significantly larger Spanish corpus and its responses are more natural for native speakers. If your use case involves customer service in Spanish, that nuance matters. A chatbot that responds with awkward grammatical constructions loses credibility with the user, regardless of how cheap the model is.

To better understand how these models work technically, check out our LLM language models guide.

When to Choose Each One

Choose DeepSeek if:

• Research and academia: you need a powerful model for scientific, mathematical or logical reasoning without paying OpenAI licenses. DeepSeek-R1's visible chain of thought is a real pedagogical advantage: you can see exactly how the model reaches each conclusion, allowing detection of errors in intermediate reasoning.
• Code generation: DeepSeek performs at GPT-4o level in code and, in some competitive programming benchmarks, surpasses it. If your team develops software and wants an economical copilot, it's the best option. Plus, being open-source, you can integrate it into your CI/CD pipeline without external API call limits.
• Limited budget: the price difference is brutal. For startups or projects with high token volume, DeepSeek allows operating at a fraction of the cost. A company processing 100 million tokens per month would pay approximately $70 with DeepSeek versus over $1,000 with GPT-4o.
• Self-hosting: being open-source, you can deploy DeepSeek-V3 on your own infrastructure. Total data control, no third-party dependency, no rate limits. This eliminates privacy issues associated with DeepSeek's cloud API.

Choose ChatGPT if:

• General use and productivity: ChatGPT has the most mature ecosystem: custom GPTs, plugins, web browsing, image generation with DALL-E, data analysis with Code Interpreter. Nothing comes close to that versatility. For non-technical teams, it's the most straightforward option.
• Enterprise integration: OpenAI offers ChatGPT Enterprise and ChatGPT Team with SOC2 compliance, DPA and EU data residency options. For companies needing contractual guarantees, security audits and dedicated support, there's no comparison.
• Multimodality: vision, voice, image generation, PDF document analysis, spreadsheets and presentations. ChatGPT is the only one offering all this in a single interface natively. DeepSeek lacks comparable multimodal capabilities today.
• Quality Spanish: if your product targets Spanish-speaking customers and linguistic quality is critical, GPT-4o remains the standard. The difference is especially noticeable in long texts, where DeepSeek tends to produce more literal and less idiomatic constructions.

For a comparison with other models, check out our articles on Claude vs ChatGPT and Perplexity vs ChatGPT.

DeepSeek for Companies: Risks

This is where the conversation gets serious. DeepSeek stores all user data on servers located in China. The company has publicly stated that European GDPR doesn't apply to them --a position that EU regulators have unanimously rejected--.

Italy was the first country to act: the Garante ordered the blocking of DeepSeek for insufficient GDPR compliance. France, Germany and Ireland have opened similar investigations. The lack of transparency about how data is processed, stored and potentially shared with the Chinese government under China's national security laws is the central problem.

DeepSeek doesn't have SOC2, ISO 27001 certifications or standard DPA (Data Processing Agreement) for European companies. This means that if you process personal data of European citizens through DeepSeek's API, you may be violating GDPR --with penalties that can reach 4% of global annual turnover--.

Additionally, Chinese national security laws require companies in the country to share data with government authorities if requested. This risk is especially relevant for companies handling sensitive data: financial, health or customer data.

The alternative for companies in Spain seeking powerful models with European regulatory compliance: Mistral (French company, EU servers, native GDPR compliance), Claude from Anthropic (DPA options and data residency in Europe) or deploy DeepSeek on your own European infrastructure using the open-source weights --thus eliminating data transfer to China--. This last option requires technical capability and adequate hardware, but it's the only one that combines DeepSeek's power with European market legal security.

Frequently Asked Questions

Is DeepSeek better than ChatGPT?

It depends on the criterion. DeepSeek surpasses ChatGPT in mathematical reasoning, code generation and cost efficiency. ChatGPT is superior in Spanish quality, multimodality and regulatory compliance. There's no absolute "better": there's the best for your use case.

Is DeepSeek free?

DeepSeek's web and mobile application is completely free, with no paid subscription plans. The API offers 5 million free tokens to new accounts and its prices are the lowest on the market: $0.28 per million input tokens. In comparison, ChatGPT charges $20/month for the Plus plan and its API prices are 6 to 25 times higher.

Is it safe to use DeepSeek in Europe?

If you use the API or web application directly, your data is processed on servers in China, which poses serious GDPR problems. If you need to use DeepSeek in a European business context, the only safe route is self-hosting: deploy the model on your own infrastructure or on a European cloud provider using the open-source weights.

Read our guides on AI applied to customer support. Explore AI Comparisons for more analysis of the models that are transforming customer service.