DeepSeek app vs ChatGPT app: which to use

DeepSeek vs ChatGPT app: which is better?

The ChatGPT app is the more complete product: voice, image generation, memory and projects, with ads on the Free and $8 Go plans. The DeepSeek app is free with no ads, but its privacy policy stores your chats in China and uses them for training unless you opt out.

Both are good at everyday questions. The choice comes down to features, ads and where your chats go.

I've used DeepSeek's models through its website and through other hosts, but I haven't used the DeepSeek phone app. Everything below about the DeepSeek app comes from its App Store and Google Play listings, DeepSeek's homepage and its privacy policy, all read on 11 October 2026. I use ChatGPT on the Go plan.

The two apps side by side

DeepSeek facts from its App Store and Google Play listings, homepage and model announcement, and its privacy policy dated 10 February 2026, all read 11 October 2026. ChatGPT facts from OpenAI's pricing page (read 11 October 2026, US prices checked 3 October 2026) and its Data Controls FAQ.

What the DeepSeek app offers

The DeepSeek app is free to download and use. Google Play shows more than 50 million downloads and a Teen rating, and the App Store lists it 13+. DeepSeek charges developers for its API, but the chat app has no paid plan.

It runs DeepSeek's own model, currently V4.1 Flash, which DeepSeek announced on 10 September 2026 with built-in image understanding. DeepSeek's homepage shows DeepThink, its step-by-step reasoning mode, and Search for current information. The app's September 2026 update notes say its Instant, Expert and Vision modes are now unified and the thinking process collapses automatically. Earlier updates added photo and file uploads. I can't tell you how the app feels day to day, because I haven't used it.

What the ChatGPT app offers

The ChatGPT app does more. It has a voice mode you can talk to, image generation, memory that carries between chats, projects that group files and chats, and deep research. Scheduled tasks start on the $8 Go plan. I find it the smoothest of the chat apps.

The free plan runs GPT-6 Luna with unlimited everyday text chats (subject to OpenAI's abuse guardrails). Its default Instant model reads about 27,000 tokens of a chat, roughly 12 pages, and Go reads about 54,000. On Go, using the default Instant model, I've had a chat lose things I told it earlier in the same conversation. Go and Plus also offer Thinking models that read up to 256,000 tokens.

Ads come with the two cheapest plans. In my writing test on 2 September 2026, ads appeared under three of the five answers captured from ChatGPT on Go. Plus at $20 removes them. Ads in AI apps covers how they work.

Privacy: where your chats go

DeepSeek's privacy policy (updated 10 February 2026) says it collects, processes and stores your personal data in the People's Republic of China. It lists what you type among the data used to "train and improve our technology", gives you a right to opt out of that training, and keeps your data "for as long as you have an account". The policy describes no settings switch for training; the route is a request to DeepSeek. The App Store privacy label lists data such as email, phone number, coarse location, photos and audio as collected for the app to work.

ChatGPT also trains on your chats by default, on every consumer plan. The difference is the switch: "Improve the model for everyone" under Settings, Data Controls, which you can turn off in a few taps.

The same pattern shows up when you call DeepSeek's service directly. OpenRouter, which connects apps to many model hosts, flags DeepSeek's own API as keeping prompts and able to train on them (OpenRouter provider data, read 11 October 2026). Of the 92 hosts OpenRouter lists, 53 are flagged as doing neither.

DeepSeek publishes its model weights, so anyone can host V4.1 Flash, and on 11 October 2026 OpenRouter listed 28 hosts serving it besides DeepSeek. Using DeepSeek's model doesn't require sending your chats to DeepSeek; using DeepSeek's app does. Are Chinese AI models safe goes further into the risks, and open weights vs closed explains how open weights work.

The lock-in problem with first-party apps

Any app made by a model lab gives you that lab's models and nobody else's. DeepSeek's app runs DeepSeek. ChatGPT runs OpenAI.

That matters because the best cheap model changes every few weeks. When another lab ships something better, the DeepSeek app can't give it to you. You'd need a new app and a new account, and your chat history stays behind. The DeepSeek app is free, so that's the whole cost. On ChatGPT the same holds, and you may also be paying a subscription to stay put.

I run a desktop app called Hermes with my own OpenRouter key, a setup for technical people. In the month to 15 September 2026, my chat spending there was spread across models from four labs: DeepSeek V4 Flash, Z.ai's GLM 5.3 Flash, Moonshot's Kimi K3 and Google's Gemini 3.7 Flash. A single lab's app would have given me one of those. You don't pick a model makes the longer case.

Which app should you use?

• Pick the ChatGPT app if you want the most complete free app, with voice, images and memory, and the ads don't bother you. Turn off training in Data Controls if you'd rather OpenAI didn't learn from your chats.
• Pick the DeepSeek app if you want a capable free assistant with no ads and no paid tier, and you're comfortable with your chats being stored in China and used for training unless you opt out.
• Pay for ChatGPT Plus if you program, your work pays for it, or you use AI professionally every day. Otherwise you don't need to pay OpenAI. Is ChatGPT Plus worth it goes through that decision.

There's a third option if you want cheap open models without one lab's app. Plainly, which I built, is $5 a month for unlimited chat. Plainly runs one capable open-source model and switches when a better one comes out. You never pick. It shows no ads and never uses your chats to train AI, and its provider account excludes hosts that train on prompts (some hosts still keep prompts for a period). It has no voice mode, image generation, memory across chats or phone app (it runs in the browser), so the ChatGPT app still does more.