If by “ChatGPT code” you mean the actual source code that powers ChatGPT from OpenAI—that isn’t open-source and can’t be downloaded.

But you have great options to run ChatGPT-like systems locally or via APIs:

Options you can download/use

1) Use OpenAI’s API (official way)

You don’t download ChatGPT, you call it via API.

pip install openai

from openai import OpenAI
client = OpenAI()
resp = client.chat.completions.create(
    model="gpt-4o-mini",
    messages=[{"role":"user","content":"Hello"}]
)
print(resp.choices[0].message.content)

• Docs: https://platform.openai.com/docs

2) Run open-source LLMs locally (free to download)

These are “ChatGPT-like” models you can run on your PC:

• Ollama (easiest way to run models locally)
  • Download: https://ollama.com
  • After install: ollama run llama3 # or: ollama pull mistral ollama run mistral ollama pull qwen2 ollama run qwen2 ollama pull phi3 ollama run phi3
• LM Studio (GUI app for Windows/Mac/Linux)
  • Download: https://lmstudio.ai
• text-generation-webui (powerful web UI)
  • Repo: https://github.com/oobabooga/text-generation-webui

Popular open models to try: Llama 3, Mistral/Mixtral, Qwen2, Phi-3, Gemma, DeepSeek-R1 (reasoning).

3) Open-source “ChatGPT-style” UIs (if you want the chat app feel)

• Open WebUI: https://github.com/open-webui/open-webui
  Works with Ollama; one-click Docker: docker run -d -p 3000:8080 --name openwebui --restart unless-stopped \ -e OLLAMA_BASE_URL=http://host.docker.internal:11434 \ ghcr.io/open-webui/open-webui:main
• Chatbot UI: https://github.com/mckaywrigley/chatbot-ui
• LibreChat: https://github.com/danny-avila/LibreChat