Editing Openai/694ab010-3e7c-8000-b0e8-b98c22b7a063 (section)

===== If Streamlit and FastAPI are in the same container: =====
* The OpenAI key is available to both
* The UI process can read it (even if you don’t intend it)
* A bug, debug print, exception, or misconfiguration can leak it

Even worse:
* Streamlit executes Python code dynamically
* Any vulnerability in UI code could expose environment variables

===== <syntaxhighlight>Frontend (UI) =====
  ❌ No secrets
  ❌ No credentials
  ❌ No cloud permissions

Backend (API)
  ✅ Has secrets
  ✅ Talks to OpenAI
  ✅ Protected behind API Gateway

</syntaxhighlight>

By physically separating containers, AWS guarantees:
* The UI container literally does not have access to the secret
* Even if the UI is compromised, the attacker still cannot call OpenAI

This is called least privilege and blast-radius reduction.

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