decorator in FAST API (Python)
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Software Engineering student at FAST-NUCES building full-stack AI-powered systems end-to-end.
I work across the full stack:
Frontend: React.js & Next.js
Backend: FastAPI & Express.js
Mobile: React Native
ML & NLP: scikit-learn, TF-IDF, Logistic Regression, Random Forest , XG-Boost , ANN.
Deployment: Docker, Render, Vercel
I don't just study ML concepts — I integrate them into real products and ship them.
Currently going deeper into backend architecture, scalable API design, MLOps, and production deployment pipelines. Because writing code is just the beginning — shipping systems that work in the real world is the goal.
@app.get("/auth")
def authenticating():
return {"isLoggedIn": "saeed here"}
@app.get("/auth")?
This is called a decorator in Python.
A decorator is something that:
Takes a function and modifies or registers it in some way.
@app.get("/auth") means:
“Whenever someone sends a GET request to /auth, run the function written below.”
How does Python read this?
Python internally converts this:
@app.get("/auth")
def authenticating():
return {"isLoggedIn": "saeed here"}
into something like this:
def authenticating():
return {"isLoggedIn": "saeed here"}
app.get("/auth")(authenticating)
So basically:
app.get("/auth")returns a functionThat function takes
authenticatingas argumentFastAPI stores it in a routing table
So FastAPI now knows:
Route: GET /auth → Call authenticating()
