Buyer’s guide 2026 edition
7 Best Open-Weight ChatGPT Alternatives in 2026
Kimi, GLM, DeepSeek and Qwen now trade blows with the closed frontier. Here is where to use them without giving up privacy, polish or real work done.
The short answer
What is the best open-weight ChatGPT alternative?
Sidekick Pro is the best open-weight ChatGPT alternative in 2026. It runs Kimi K3, GLM 5.3, DeepSeek V4.1 Flash and Qwen 3.8 Max through providers that do not train on your prompts, and puts them to work in your email, calendar and browser, from $59 a month. Mistral Vibe suits Europe, Lumo suits privacy, Kimi and DeepSeek suit free use, and Ollama runs models on your own computer.
Our top picks at a glance
An open-weight model is one whose trained weights anyone can download, run and fine-tune. ChatGPT runs on models only OpenAI can host. With an open-weight model, any provider can serve it, and you can switch providers without switching models.
This year the gap closed. Moonshot published the weights of Kimi K3 in July, Z.ai released GLM 5.3 in August, Alibaba opened its first Max-class Qwen model, and DeepSeek shipped V4.1 Flash under the MIT license in September. For a lot of everyday work, the best open models are now good enough that the question is no longer the model. It is the app around it.
That app decides where your chats are stored, whether they train the next model, and whether the assistant does more than talk. We ranked the apps that put open-weight models in front of you on all three.
1. Sidekick Pro
AI agents for your email, calendar, calls and browser
The leading open-weight models in an assistant that does real work in your email, calendar and browser, with no training on your prompts.
Sidekick Pro lets you pick Kimi K3, GLM 5.3, DeepSeek V4.1 Flash or Qwen 3.8 Max for any chat, and switch to GPT, Claude or Gemini in the same conversation when a task needs it. You get the open models' price and speed for everyday work without losing the closed frontier for the hard cases.
Every request goes only to inference providers that have agreed not to train on your prompts. That matters more for open models than for closed ones, because the same model is served by many hosts with different terms, and the model maker's own app often trains on your chats by default.
The model is only half of it. Sidekick Pro reads every email and flags what matters, keeps your calendar straight, sends a morning brief, and clicks, types and fills in forms in your own browser. It answers calls and texts on its own phone number, and on the Business plan it joins your Zoom and Google Meet calls.
Open models are now good enough. The app around them decides whether your data stays yours and whether the work gets done.
- Four open-weight flagships Kimi K3, GLM 5.3, DeepSeek V4.1 Flash and Qwen 3.8 Max in one model picker.
- No training on your prompts Requests go only to providers that have agreed not to train on them.
- Closed models too Switch to GPT, Claude or Gemini mid-chat, in the same plan.
- Inbox and calendar Reads every email, flags what matters, drafts replies and sends a daily brief.
- Your own browser Clicks, types and fills in forms in your own browser, with the logins you already have.
- Everywhere you are Web, Chrome, iOS, Android, Mac and Windows apps, with voice control.
What we like
- Kimi, GLM, DeepSeek and Qwen beside GPT, Claude and Gemini in one plan
- Prompts never go to a provider that trains on them
- An assistant that acts in your email, calendar and browser, not only a chat box
- Team workspace to share skills, documents and data
Keep in mind
- Hosted for you, so you cannot run the models on your own hardware
- No free plan and no trial; it starts on a paid plan
From $59/mo
Personal $59/mo · Business $149/mo
Best for: Anyone who wants open-weight models for real daily work without handing their chats to the model maker.
Best for Europe
2. Mistral Vibe
European AI assistant, formerly Le Chat by Mistral AI
A polished European assistant whose default model is open-weight, with EU hosting and connectors to Gmail and Google Calendar.
Mistral renamed Le Chat to Vibe in August 2026. Its default model, Mistral Medium 3.5, is a 128B model whose weights Mistral published in April under a modified MIT license. Vibe adds web search, image generation, voice, a knowledge base, scheduled tasks and more than 100 connectors.
Mistral hosts your data in the EU by default. On the free plan your chats can train its models unless you turn that off; the paid plans do not train on them by default.
What we like
- Free plan, and Pro is $14.99 a month
- Hosted in the EU by a French company
- Connectors to Gmail, Google Calendar and many more
Keep in mind
- The free plan trains on your chats unless you opt out
- One lab's models only
- Price
- Pro $14.99/mo · Team $24.99/user/mo · Enterprise custom
- Platforms
- Web, iOS, Android
- Best for
- Europeans and teams who want an open-weight default model hosted in the EU.
Best for privacy
3. Lumo
Private AI assistant with encrypted chat history by Proton
The most private chat here, built only on open models, with no logs and chat history encrypted so that even Proton cannot read it.
Lumo comes from Proton, the Swiss company behind Proton Mail. It runs open models such as Qwen and GLM, plus the Swiss Apertus model, on servers Proton controls in Europe. Proton says it keeps no logs, encrypts your chat history with zero-access encryption, and never uses your chats for training.
Lumo 2.0 added image generation and editing, better web search, memory and projects. It is a chat assistant, not an agent, so it does not act in your inbox or browser.
What we like
- Zero-access encryption and no logs
- Never trains on your chats
- Free plan, and Lumo Plus from $9.99 a month billed yearly
Keep in mind
- The free plan keeps chat history for only 7 days
- Chats only; it does not act in your email or browser
- Price
- Lumo Plus $12.99/mo, or $9.99/mo billed yearly
- Platforms
- Web, iOS, Android
- Best for
- People who want the most private hosted chat and are happy with a chat-only assistant.
Best from a model maker
4. Kimi
AI assistant and agent built on Kimi models by Moonshot AI
The home of Kimi K3, one of the strongest open-weight models, with a capable agent mode and a free plan.
Kimi is Moonshot AI's own app. It runs Kimi K3, whose weights Moonshot published in July 2026, and the faster Kimi K2.6. Its OK Computer agent builds websites, slides, documents and spreadsheets, and it has deep research, memory across chats and image generation.
The trade-off is data. Kimi's help pages say chats may be used for training after de-identification, that opting out takes an email to support, and that data is stored in mainland China.
What we like
- The newest Kimi model, straight from its maker
- Strong agent for slides, sites and documents
- Free plan, with apps for web, phone and desktop
Keep in mind
- Trains on your chats by default; opting out takes an email
- Data stored in mainland China, per Kimi's help pages
- Price
- Moderato $19/mo · Allegretto $39/mo · Allegro $99/mo · Vivace $199/mo (less when billed yearly)
- Platforms
- Web, iOS, Android, Mac, Windows
- Best for
- People who want Kimi K3 and its agent mode and are comfortable with where the data goes.
Best free option
5. DeepSeek
Free AI chatbot built on DeepSeek models by DeepSeek
A capable chatbot on MIT-licensed models that costs nothing, if you accept that your data is stored in China.
DeepSeek's app runs its own V4 family, released under the MIT license, including V4.1 Flash from September 2026. It has web search, a DeepThink reasoning mode and file upload, and it is free with no paid tier.
DeepSeek's privacy policy says your data is stored in the People's Republic of China and may train its models unless you turn that off in settings. Several governments, including Australia, Taiwan, New York State and Oklahoma, ban it on government devices.
What we like
- Free, with no paid tier to upsell
- Models released under the MIT license
- Web search and a reasoning mode
Keep in mind
- Data stored in China, and trains on chats by default
- Banned on government devices in several countries and US states
- Price
- The app is free; developers pay per use for the API
- Platforms
- Web, iOS, Android
- Best for
- Personal use where cost matters most and the data is not sensitive.
Best for images and voice
6. Qwen Chat
Free AI assistant built on Qwen models by Alibaba
A free all-rounder from Alibaba with image generation, voice and video chat, and deep research.
Qwen Chat gives you Alibaba's Qwen models, a mix of open-weight and proprietary ones. Qwen 3.8, released in August 2026, includes Alibaba's first Max-class model with public weights. The app adds image generation and editing, voice and video chat, document analysis and deep research.
It is free to use. Alibaba's privacy policy says de-identified content may be used to train its models and that inputs are processed in Singapore.
What we like
- Free, with no paid tier needed
- Image generation, voice and video chat in one app
- Apps for web, phone and desktop
Keep in mind
- Mixes open-weight and proprietary models
- The policy allows training on de-identified content
- Price
- Free to use
- Platforms
- Web, iOS, Android, Mac, Windows
- Best for
- People who want a free assistant for images, voice and research.
Best for your own computer
7. Ollama
Run open models on your own computer by Ollama
The simplest way to run open-weight models on your own machine, free and open source, with an optional cloud for the big ones.
Ollama downloads and runs open models such as Kimi, GLM, DeepSeek, Qwen, Gemma and gpt-oss on your Mac, Windows or Linux computer. When a model runs locally, your prompts never leave the machine. It is open source under the MIT license.
The flagship models are too large for most computers, so Ollama Cloud runs them for you from $20 a month, with no prompt logging and no training. Ollama is a chat app and a developer tool; it does not act in your inbox or calendar.
What we like
- Free and open source (MIT)
- Local models keep every prompt on your machine
- Cloud plans for models too big for your computer
Keep in mind
- The best models need a powerful computer or a cloud plan
- No mobile app, and no work in your email or calendar
- Price
- Free and open source (MIT) for local use · Cloud Pro $20/mo · Max $100/mo
- Platforms
- Mac, Windows, Linux
- Best for
- Developers and tinkerers who want models on their own hardware.
Open-Weight ChatGPT Alternatives compared, side by side
Starting prices come from each vendor’s own site. Scroll the chart sideways on a small screen.
| Feature | Our pick Sidekick Pro | Mistral Vibe | Lumo | Kimi | DeepSeek | Qwen Chat | Ollama |
|---|---|---|---|---|---|---|---|
| Starting price | From $59/mo | From $14.99/mo | From $12.99/mo | From $19/mo | Free | Free | Free |
| Free plan | No | Yes | Yes | Yes | Yes | Yes | Yes |
| Open-weight models | Kimi K3, GLM 5.3, DeepSeek V4.1, Qwen 3.8 | Mistral Medium 3.5 | Qwen, GLM, Apertus | Kimi K3, K2.6 | DeepSeek V4 family | Qwen family | Kimi, GLM, DeepSeek, Qwen, more |
| GPT, Claude and Gemini in the same app | Yes | No | No | No | No | No | No |
| No training on your chats by default | Yes | Paid plans only | Yes | No | No | De-identified data | Yes |
| Where your data is stored | United States | EU | Europe | Mainland China | China | Singapore | Your computer |
| Works in your email and calendar | Yes | Connectors | No | Not listed | Not listed | Not listed | No |
| Agent that does tasks for you | Email, calendar, browser, phone | Work mode and scheduled tasks | No | OK Computer agent | Not listed | Deep research | Tool calling |
| Image generation | Yes | Yes | Yes | Yes | Not listed | Yes | Not listed |
| Runs on your own computer | No | No | No | No | No | No | Yes |
| Our score | 9.4 | 8.5 | 8.2 | 8.0 | 7.7 | 7.5 | 7.3 |
How we chose and scored every open-weight ChatGPT alternative
We scored each app on how well it delivers open-weight models for everyday work, and on what it does with your data. "Not listed" in the chart means the vendor does not list that feature; prices and privacy terms come from each vendor's own site on the date shown.
- Real work done 30%
Does it only chat, or does it act in your email, calendar, browser and files?
- Privacy and data location 30%
Does it train on your chats by default, and where is your data stored?
- Open-weight model choice 20%
How many leading open-weight models it offers, and how current they are.
- Ease and price 20%
Can a non-technical person start in minutes, and what does daily use cost?
Editor’s pick for 2026
Sidekick Pro gives you the best open-weight models without giving your chats to the model maker.
Most open-weight apps on this list are the model maker's own chatbot, and several train on your chats by default or store them in China. Sidekick Pro runs the same models through providers that do not train on your prompts, and lets you switch to GPT, Claude or Gemini when a task needs them.
It also does the work, not just the chat, in your email, calendar and browser. Personal is $59 a month for one person and Business is $149 a month for a whole team, with no free plan and no trial.
Frequently asked questions
What is an open-weight AI model?
An open-weight model is one whose trained weights the maker publishes, so anyone can download, run, host and fine-tune it. Kimi K3, GLM 5.3, DeepSeek V4.1 Flash, Qwen 3.8 and Mistral Medium 3.5 are open-weight. The models behind ChatGPT are not; only OpenAI can serve them.
Is open-weight the same as open source?
Not always. Open-weight means the weights are public. Many open-weight models also ship under an open-source license such as MIT or Apache 2.0, but some use custom licenses with extra conditions for very large companies, such as a duty to show the model name. Read the license before you build a product on one.
What is the most private open-weight ChatGPT alternative?
Running a model on your own computer with Ollama is the most private, because your prompts never leave the machine. Among hosted apps, Lumo keeps no logs and encrypts your chat history. Sidekick Pro sends prompts only to providers that have agreed not to train on them.
Is DeepSeek safe to use?
DeepSeek's privacy policy says your data is stored in China and may train its models unless you opt out, and several governments ban the app on government devices. You can use DeepSeek's models without its app, through Sidekick Pro, Ollama or another provider that hosts the open weights.
Which open-weight model is the best?
It depends on the task, and the lead changes every few months. In 2026, Kimi K3, GLM 5.3, Qwen 3.8 and DeepSeek V4.1 Flash are the strongest general-purpose open-weight models. An app that offers several of them, like Sidekick Pro, lets you switch instead of committing to one lab.