DeepSeek vs ChatGPT: the difference that matters is where your data goes

DeepSeek vs ChatGPT is mostly a question about data, not features. Both are chat assistants on top of large language models, both answer questions, write and code, and both have APIs for developers. The difference that matters most is where your conversations go: DeepSeek's privacy policy says it collects, processes and stores personal data in the People's Republic of China, and in January 2025 Italy's data protection authority ordered it to stop processing the data of people in Italy. ChatGPT is run by OpenAI, which for Europe names an Irish company as controller and lets you switch off training in settings. This comparison uses the two companies' own documents, checked on October 10, 2026, and does not rank answer quality.

DeepSeek vs ChatGPT at a glance

Table: DeepSeek and ChatGPT compared from their own documents (October 10, 2026)

Plans and price

ChatGPT publishes its plans. Seen from Spain on October 10, 2026, the page lists Free at €0 with "unlimited text chats with GPT-6" subject to abuse guardrails, Go at €8 (a plan that "may include ads"), Plus at €23 and Pro from €103; OpenAI's help center gives Plus as $20 a month and Pro in three tiers of $100, $200 and $500 in the US. Our guide to ChatGPT pricing goes plan by plan.

DeepSeek does not publish a consumer price list. Its pricing page covers only the API, its homepage points to the web chat, the apps and an agent tool called DeepSeek Harness, and the chat asks you to sign in with a phone number, an email address, Google or Apple before showing anything. Its terms of use, updated March 27, 2026, mention no fees for the chat. In August 2026 DeepSeek said V4 Pro was available in the app and on the web through "Expert Mode".

For developers the comparison is clearer, because both publish API prices. DeepSeek V4.1 Flash costs $0.30 per million input tokens and $1.20 per million output tokens at peak hours, half that off-peak; OpenAI's GPT-6 Luna costs $0.10 and $0.50, and GPT-6.1 Sol $2 and $10. In other words, DeepSeek is no longer the cheapest API per token. The details are in our guide to DeepSeek API pricing.

Where your data goes

DeepSeek. Its privacy policy, last updated February 10, 2026, states: "we directly collect, process and store your Personal Data in People's Republic of China". It lists improving and developing the services and training and improving its technology, "such as our machine learning models", among the purposes. Among the rights it says may be available to you is "the right to opt-out of using your Personal Data for training our models", exercised by emailing privacy@deepseek.com. A separate document on how its models are trained says user input may be used for a small part of the training data, with encryption, de-identification and anonymization, and points to the privacy policy to opt out. DeepSeek names Prighter Group as its privacy representative in the EU and the UK, and says it may share data with law enforcement and public authorities when it believes this is necessary to comply with applicable law, legal process or government requests.

ChatGPT. OpenAI's help center says it may use content from personal plans such as ChatGPT to train its models, and that you can opt out by turning off "Improve the model for everyone" in Settings, under Data controls; business plans and the API are not used for training by default. For people in the EEA and Switzerland, its European privacy policy names OpenAI Ireland Limited as controller and the Irish Data Protection Commission as lead authority. Our guide is ChatGPT safe? covers the settings in detail.

What regulators have said

On January 30, 2025, Italy's data protection authority, the Garante, ordered the two DeepSeek companies to limit, with immediate effect, the processing of personal data of people in Italy. In its decision the authority found that DeepSeek offers its service to people in the EU and is therefore subject to the GDPR, which the companies had disputed; that its privacy policy was incomplete; that data stored in China raised concerns under the GDPR's security rules; and that it had not named an EU representative at the time. The decision also records that the app had disappeared from Apple's and Google's stores in Italy. We did not find a later decision lifting the limitation; if you are in Italy, check the Garante's website.

For a business, Regulation (EU) 2024/1689 adds its own duties on top of data protection whichever assistant you pick; our guide to the Regulation (EU) 2024/1689 explains what applies to companies that use chatbots.

Models, context and running it yourself

DeepSeek's current model is V4.1 Flash, released on September 10, 2026, which DeepSeek describes as a 552 billion parameter mixture-of-experts model that reads images natively; V4 Pro remains available. In the API both read up to 1 million tokens. DeepSeek also published V4.1 Flash's weights and technical report on Hugging Face, so the model can in principle run on your own hardware, although its size puts it far beyond an ordinary PC.

ChatGPT's plans page lists GPT-6.1 Sol, GPT-6 Astra, GPT-6 Sol and GPT-6 Luna among its models, and gives the free plan's instant model a 27,000-token context window, about 12 pages of input. OpenAI does not publish the weights of these models.

If keeping data on your own machine is the real goal, a smaller open model running locally avoids both companies; see our guide to running an LLM locally.

Which one to use

• You work with personal or company data in the EU: ChatGPT with training switched off, or a business plan, is the easier fit with data protection rules; DeepSeek stores data in China.
• You only want to try a capable model on public information: either works; test both on your own questions.
• You build software on an API: compare the cost of your own workload; DeepSeek's prices are low, but GPT-6 Luna and Claude Haiku 5.5 now list lower ones.
• You want neither company to see your data: run an open model locally.

For other options, from Claude and Gemini to Mistral, see our ChatGPT alternatives.