diff --git a/README.md b/README.md
index a6dfabc..9337a40 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,9 @@ echo "OPENAI_API_KEY=sk-your-key" > .env
 poetry install
 poetry shell
 poetry run uvicorn main:app --reload --port 7001
+
+# Useful for debugging purposes when you don't want to waste GPT4-Vision credits
+MOCK=true poetry run uvicorn main:app --reload --port 7001
 ```
 
 Run the frontend:
diff --git a/backend/main.py b/backend/main.py
index 72b4dd7..1dc9333 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -33,7 +33,7 @@ app.add_middleware(
 
 # Useful for debugging purposes when you don't want to waste GPT4-Vision credits
 # Setting to True will stream a mock response instead of calling the OpenAI API
-SHOULD_MOCK_AI_RESPONSE = False
+SHOULD_MOCK_AI_RESPONSE = os.environ.get("MOCK", False)
 
 
 app.include_router(screenshot.router)