How to Build Your Own Private ChatGPT for Free

By the end of this guide, you'll have a ChatGPT-like web interface running on your own computer. It will:

• Look and feel like ChatGPT (conversation history, markdown, code highlighting)
• Run 100% locally — no internet needed, no data sent anywhere
• Cost $0/month to operate
• Support multiple models (switch between chat, coding, reasoning)
• Have an OpenAI-compatible API for tools and integrations

Mac/Linux: curl -fsSL https://ollama.com/install.sh | sh

Windows: Download from ollama.com/download

Verify: ollama --version

Choose based on your VRAM (run nvidia-smi or check System Info on Mac):

• 8 GB: ollama pull qwen3:8b
• 12-16 GB: ollama pull qwen3:14b
• 24 GB: ollama pull qwen2.5-coder:32b

Not sure? Use FitMyLLM to find the best model for your exact hardware.

With Docker (recommended):

docker run -d -p 3000:8080 --add-host=host.docker.internal:host-gateway -v open-webui:/app/backend/data --name open-webui ghcr.io/open-webui/open-webui:main

Without Docker:

pip install open-webui && open-webui serve

Open http://localhost:3000 — you now have ChatGPT running locally.

• Chat privately — medical questions, legal advice, personal conversations. Nothing is logged.
• Code assistance — paste your codebase, ask for reviews, generate tests. No code leaves your machine.
• Document analysis — upload PDFs and ask questions about them (RAG built into Open WebUI).
• API access — any tool that works with OpenAI API works with Ollama. Just set OPENAI_API_BASE=http://localhost:11434/v1
• Multiple models — switch between chat, coding, and reasoning models in the UI. Download as many as your storage allows.

Total cost: $0. Total setup time: 10-15 minutes. Total data sent to the cloud: zero bytes.