DeepSeek vs ChatGPT: Open Weights, Privacy, and Which to Use

DeepSeek vs ChatGPT isn't really a contest between two chatbots. It's a choice between a model you can own and a product you rent. DeepSeek publishes its model weights under the MIT licence and sells a cheap, standard-format API. ChatGPT is a closed service with far more features built around the model: image generation, voice, agents, custom GPTs, desktop apps.

On everyday answer quality, the two are close enough that a leaderboard won't settle it, and both release new models too often for any ranking to last. What lasts is the shape of each product. Four differences decide it:

• Open weights. You can download DeepSeek's models and run them on hardware you control. You can't do that with the models behind ChatGPT.
• App vs API. DeepSeek's hosted chat app and its API are different products with different data rules. Most "is DeepSeek safe" arguments mix them up.
• Where your data goes. DeepSeek's own privacy policy says it stores what it collects on servers in China. That alone rules it out for some jobs.
• Feature breadth. ChatGPT does more things. If you need images, voice, or a finished agent product, that ends the comparison.

Quick comparison

Where DeepSeek is stronger

You can actually own the model. This is the difference that matters most, and it's the one that won't change next month. DeepSeek publishes its model weights on Hugging Face, and the model card says plainly that "the model weights are licensed under the MIT License." That's about as permissive as licences get. You can run the model commercially, fine-tune it, and host it inside your own network, where no prompt ever leaves the building.

There's a catch, and most write-ups skip it. As of September 2026, DeepSeek's current flagship models range from hundreds of billions to more than a trillion parameters. That's data-centre hardware, not a laptop. On Ollama, the newest DeepSeek models are listed as cloud models, and the sizes that fit on a personal machine come from an older model family. So "open weights" means your company can self-host it long before it means you can run it on your MacBook. If running on your own machine is the real goal, our guide to running AI agents locally covers what the setup takes.

The API is cheap and speaks a standard format. DeepSeek's API docs say its API is compatible with both the OpenAI and Anthropic formats. In practice you change a base URL and a key, and existing code or tools keep working. Billing is per token from a prepaid balance. Cached input costs less than fresh input, and off-peak hours cost half the peak rate. If you're pushing high volumes through an API, it's worth doing the maths against your current bill.

It plugs into the coding agents you already use. DeepSeek's docs list setup guides for Claude Code, Codex, OpenCode, and other agent tools, so it can run as the model behind an agent you've already configured. The API also supports tool calls, JSON output, and (in beta) fill-in-the-middle completion for code.

Long context by default. Both of DeepSeek's current API models support a context window of one million tokens, per its pricing page. That's enough for a whole codebase or a long contract in one request.

Where ChatGPT is stronger

It does far more things. ChatGPT generates images, holds realtime voice conversations, runs deep research reports, and ships an agent that carries out multi-step tasks. It also has Codex for coding, custom GPTs, and memory. DeepSeek's chat app covers the core: chat, a reasoning mode, web search, and reading images. Anything past that, it doesn't do.

Image generation, specifically. OpenAI documents dedicated image generation models. DeepSeek's newest model reads and understands images, but its API docs list no model that creates them. If pictures are part of your work, the comparison ends here.

Clearer data controls for business use. OpenAI's API data policy says data sent to the API isn't used to train its models unless you opt in. Eligible API projects can also pin where content is stored at rest to a chosen region. ChatGPT users can opt out of having their chats used for training. For a company with a compliance team, that paperwork often decides things before anyone compares model quality.

It's a finished product on every device. ChatGPT has native desktop apps on Mac and Windows alongside web and mobile. DeepSeek offers web, iOS, and Android. If you want an assistant on your desktop and synced with your phone, ChatGPT is the more complete experience.

The privacy question, answered from the source

This is where most "DeepSeek vs ChatGPT" posts either panic or wave it away. Here is what DeepSeek's privacy policy (last updated February 2026) actually says:

Three practical consequences follow.

The app and the open weights are different risks. Everything in that table applies to DeepSeek's hosted service. If you run the open weights on your own hardware, or through a host you already trust, your prompts never reach DeepSeek at all. "Is DeepSeek safe?" has two answers, depending on which DeepSeek you mean.

Some employers and governments have already decided. Australia's Department of Home Affairs directed agencies to keep DeepSeek products off government systems, and several other countries restricted the app in 2025. The DeepSeek chatbot's Wikipedia entry tracks the list. If you work somewhere with a vendor approval process, check it before pasting anything in.

Answers on some topics are filtered. The hosted app applies content moderation under Chinese regulations, which limits its answers on subjects such as Tiananmen Square and Taiwan's political status. For most work questions you'll never notice. For research on politics or current affairs, you will.

DeepSeek vs ChatGPT for coding

Both are capable coding assistants for the everyday stuff: explaining an error, writing a function, refactoring a file. The difference is in how you use them.

Nothing stops you splitting the work: a polished agent for interactive sessions, and a cheaper open-weight model behind batch jobs or background agents. Our AI coding assistants comparison covers the wider field.

How to choose

Ask what you're actually doing with it.

• Using a chat app for everyday work → ChatGPT. More features, clearer data controls, apps on every device.
• Making lots of API calls → DeepSeek, for the per-token cost. Check the data policy fits first.
• Handling sensitive or regulated data → Either ChatGPT's business data controls or DeepSeek's weights on your own infrastructure. Not DeepSeek's hosted app.
• You need images or voice → ChatGPT. DeepSeek doesn't compete here.
• You want a model you control and can modify → DeepSeek's open weights. If a local runner is part of the plan, see our Ollama alternatives roundup.

If neither fits, our list of ChatGPT alternatives sorts the field by job instead of by hype.

What neither one keeps for you

Both are good at finishing a task and poor at leaving anything behind. You work out a good prompt, get the output you wanted, and next week you start from a blank chat again. Choosing DeepSeek over ChatGPT, or the reverse, doesn't change that.

Taku works on that gap. It's an AI-native desktop workspace where you mirror an app, skill, or workflow someone already got working, run it, remix it for your own files, and keep it instead of re-prompting from scratch. If that sounds like your week, the free app library is the quickest way to see what that looks like. Taku is in Beta, and the Mac app is available now.

Key points

• DeepSeek's model weights are open under the MIT licence. ChatGPT's models are closed.
• Open weights mean self-hosting for companies with serious hardware. The newest DeepSeek models won't fit on a laptop.
• DeepSeek's API is cheap, per-token, and compatible with OpenAI and Anthropic formats, so it drops into existing tools.
• DeepSeek's privacy policy says hosted data is stored in China and may be used for training, with a right to refuse.
• ChatGPT leads on feature breadth: image generation, voice, agents, custom GPTs, and desktop apps.
• The hosted DeepSeek app and self-hosted DeepSeek weights carry very different privacy risks. Decide which one you mean.

FAQ

Is DeepSeek better than ChatGPT?

Not across the board. DeepSeek is the better pick for cheap API usage and for anyone who wants open weights to self-host. ChatGPT is the better product for most people using a chat app, because it does far more: images, voice, agents, and desktop apps. On plain answer quality they trade places often enough that it shouldn't decide things.

Is DeepSeek open source?

Its model weights are published under the MIT licence, which allows commercial use, modification, and redistribution. The hosted chat app is a separate thing: a service with its own privacy policy, whatever the licence on the weights.

Is it safe to use DeepSeek?

It depends which DeepSeek you mean. The hosted app stores data on servers in China and may use your inputs for training, according to its own privacy policy. Running the open weights on your own hardware sends nothing to DeepSeek. Check your employer's policy before using the app for work.

Is DeepSeek or ChatGPT better for coding?

For a complete coding agent, ChatGPT's Codex is the more finished product. For a low-cost model behind a coding tool you already use, DeepSeek's compatible API works well and has documented setups for Claude Code, Codex, and OpenCode.

Can I run DeepSeek locally?

Yes, but the current flagship models need data-centre hardware. Smaller DeepSeek models from an older family run on a personal computer through tools like Ollama.

Does DeepSeek generate images?

No. DeepSeek's newest model can read and understand images, but its docs list no image generation model. ChatGPT generates images natively.