diff --git a/app/app.py b/app/app.py
index 32fed97..9d986fa 100644
--- a/app/app.py
+++ b/app/app.py
@@ -1,63 +1,62 @@
 # app/app.py
 
 import os
-from fastapi import FastAPI, Security, File, UploadFile
+import hashlib
+from slowapi import Limiter, _rate_limit_exceeded_handler
+from slowapi.errors import RateLimitExceeded
+from slowapi.middleware import SlowAPIMiddleware
+from fastapi import FastAPI, Security, File, UploadFile, Request
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
 from .schema import (
-  MenuSchema,
-  AddStaffSchema,
-  UpdateStaffEmailSchema,
-  UpdateMenuItemSchema,
-  MenuScanResponse,
-  CreateOrderSchema,
-  UpdateOrderStatusSchema,
-  UpdateUserProfileSchema,
-  VerifyPickupSchema,
-  VerifyPaymentSchema,
-  UpdateStaffProfileSchema,
-  UpdateResalePriceSchema
-)
-from .auth import (
-  authenticate_student,
-  verify_staff_access
+  MenuSchema, AddStaffSchema, UpdateStaffEmailSchema, UpdateMenuItemSchema,
+  MenuScanResponse, CreateOrderSchema, UpdateOrderStatusSchema,
+  UpdateUserProfileSchema, VerifyPickupSchema, VerifyPaymentSchema,
+  UpdateStaffProfileSchema, UpdateResalePriceSchema
 )
+from .auth import authenticate_student, verify_staff_access
 from .staff import (
-  upload_menu,
-  get_menu,
-  scan_menu_image,
-  update_menu_item,
-  delete_menu_item,
-  add_staff_member,
-  get_stall_orders,
-  update_order_status_staff,
-  get_staff_me,
-  verify_order_pickup,
-  activate_staff,
-  update_staff_profile,
-  get_stall_resale_items,
-  update_resale_price
+  upload_menu, get_menu, scan_menu_image, update_menu_item, delete_menu_item,
+  add_staff_member, get_stall_orders, update_order_status_staff, get_staff_me,
+  verify_order_pickup, activate_staff, update_staff_profile,
+  get_stall_resale_items, update_resale_price
 )
 from .manager import (
-  get_my_staff,
-  remove_staff_member,
-  update_staff_email,
+  get_my_staff, remove_staff_member, update_staff_email,
   get_stall_performance_overview
 )
 from .user import (
-  get_user_menu,
-  create_payment_order,
-  get_user_orders,
-  verify_payment_and_update_order,
-  update_user_profile,
-  cancel_order,
-  get_discounted_feed,
-  buy_resale_item
+  get_user_menu, create_payment_order, get_user_orders,
+  verify_payment_and_update_order, update_user_profile, cancel_order,
+  get_discounted_feed, buy_resale_item
 )
 from .webhook import router as webhook_router
 
+def rate_limit_key(request: Request):
+  """
+    Generate a rate limiting key.
+    Uses Authorization token when available, otherwise falls back to IP address.
+  """
+  auth_header = request.headers.get("authorization")
+
+  if auth_header:
+    token_hash = hashlib.sha256(auth_header.encode()).hexdigest()
+    return f"user:{token_hash}"
+
+  forwarded = request.headers.get("x-forwarded-for")
+  if forwarded:
+    return f"ip:{forwarded.split(',')[0].strip()}"
+
+  return f"ip:{request.client.host}"
+
+limiter = Limiter(key_func=rate_limit_key)
+
 app = FastAPI()
 
+app.state.limiter = limiter
+app.add_exception_handler(RateLimitExceeded, _rate_limit_exceeded_handler)
+app.add_middleware(SlowAPIMiddleware)
+
 app.add_middleware(
     CORSMiddleware,
     allow_origins=[
@@ -78,80 +77,110 @@
 
 security = HTTPBearer()
 
-
 @app.get("/health", tags=["health"])
-def health_check():
-    return {
-        "status": "ok",
-        "service": "greenplate-backend",
-        "environment": os.getenv("ENV", "development")
-    }
+@limiter.limit("10/minute")
+def health_check(request: Request):
+  """
+    Health check endpoint for monitoring service availability.
+  """
+  _ = request
+  return {
+      "status": "ok",
+      "service": "greenplate-backend",
+      "environment": os.getenv("ENV", "development")
+  }
 
 app.include_router(webhook_router)
 
 @app.post('/auth/verify-staff', tags=["auth"])
-async def verify_staff_endpoint(credentials: HTTPAuthorizationCredentials = Security(security)):
+@limiter.limit("5/minute")
+async def verify_staff_endpoint(
+    request: Request,
+    credentials: HTTPAuthorizationCredentials = Security(security)
+):
     return await verify_staff_access(credentials.credentials)
 
 @app.post('/auth/verify-student', tags=["auth"])
-async def verify_student_endpoint(credentials: HTTPAuthorizationCredentials = Security(security)):
+@limiter.limit("5/minute")
+async def verify_student_endpoint(
+    request: Request,
+    credentials: HTTPAuthorizationCredentials = Security(security)
+):
     return await authenticate_student(credentials.credentials)
 
 @app.patch("/user/profile", tags=["user"])
+@limiter.limit("10/minute")
 async def update_profile_endpoint(
+    request: Request,
     profile_data: UpdateUserProfileSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await update_user_profile(profile_data, credentials.credentials)
 
 @app.get("/user/menu", tags=["user"])
+@limiter.limit("30/minute")
 async def get_student_menu_endpoint(
+    request: Request,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await get_user_menu(credentials.credentials)
 
 @app.get("/user/feed/discounted", tags=["user"])
+@limiter.limit("30/minute")
 async def get_discounted_feed_endpoint(
+    request: Request,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await get_discounted_feed(credentials.credentials)
 
 @app.post("/user/order/create", tags=["user"])
+@limiter.limit("5/minute")
 async def create_order_endpoint(
+    request: Request,
     order_data: CreateOrderSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await create_payment_order(order_data, credentials.credentials)
 
 @app.get("/user/orders", tags=["user"])
+@limiter.limit("20/minute")
 async def get_student_orders_endpoint(
+    request: Request,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await get_user_orders(credentials.credentials)
 
 @app.post("/user/order/verify",tags=["user"])
+@limiter.limit("5/minute")
 async def verify_order_endpoint(
+    request: Request,
     payment_data: VerifyPaymentSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await verify_payment_and_update_order( payment_data, credentials.credentials )
 
 @app.post("/user/order/{order_id}/cancel", tags=["user"])
+@limiter.limit("5/minute")
 async def cancel_order_endpoint(
+    request: Request,
     order_id: str,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await cancel_order(order_id, credentials.credentials)
 
 @app.post("/user/resale/{resale_id}/buy", tags=["user"])
+@limiter.limit("10/minute") # Prevent race-condition spamming on hot items
 async def buy_resale_item_endpoint(
+    request: Request,
     resale_id: str,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await buy_resale_item(resale_id, credentials.credentials)
 
 @app.get("/staff/performance/overview", tags=["manager"])
+@limiter.limit("10/minute")
 async def get_stall_performance_overview_endpoint(
+    request: Request,
     month: int,
     year: int,
     credentials: HTTPAuthorizationCredentials = Security(security)
@@ -159,27 +188,35 @@ async def get_stall_performance_overview_endpoint(
     return await get_stall_performance_overview(month, year, credentials.credentials)
 
 @app.post('/staff/add-member', tags=["manager"])
+@limiter.limit("5/minute")
 async def add_staff_endpoint(
+    request: Request,
     staff_data: AddStaffSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await add_staff_member(staff_data, credentials.credentials)
 
 @app.get('/staff/list', tags=["manager"])
+@limiter.limit("20/minute")
 async def get_staff_list_endpoint(
+    request: Request,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await get_my_staff(credentials.credentials)
 
 @app.delete('/staff/{staff_uid}', tags=["manager"])
+@limiter.limit("5/minute")
 async def remove_staff_endpoint(
+    request: Request,
     staff_uid: str,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await remove_staff_member(staff_uid, credentials.credentials)
 
 @app.put('/staff/{staff_uid}/email', tags=["manager"])
+@limiter.limit("5/minute")
 async def update_staff_email_endpoint(
+    request: Request,
     staff_uid: str,
     update_data: UpdateStaffEmailSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
@@ -187,46 +224,60 @@ async def update_staff_email_endpoint(
     return await update_staff_email(staff_uid, update_data.new_email, credentials.credentials)
 
 @app.post("/staff/activate",tags=["staff", "manager"])
+@limiter.limit("5/minute")
 async def activate_staff_endpoint(
+    request: Request,
     credentials:HTTPAuthorizationCredentials = Security(security)
 ):
     return await activate_staff(credentials.credentials)
 
 @app.get("/staff/me", tags=["staff", "manager"])
+@limiter.limit("20/minute")
 async def get_staff_me_endpoint(
+    request: Request,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await get_staff_me(credentials.credentials)
 
 @app.patch("/staff/profile", tags=["staff", "manager"])
+@limiter.limit("10/minute")
 async def update_staff_profile_endpoint(
+    request: Request,
     profile_data: UpdateStaffProfileSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await update_staff_profile(profile_data, credentials.credentials)
 
 @app.post("/staff/menu", tags=["staff", "manager"])
+@limiter.limit("5/minute")
 async def upload_menu_endpoint(
+    request: Request,
     menu_data: MenuSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await upload_menu(menu_data, credentials.credentials)
 
 @app.get("/staff/menu", tags=["staff", "manager"])
+@limiter.limit("30/minute")
 async def get_staff_menu(
+    request: Request,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await get_menu(credentials.credentials)
 
 @app.post("/staff/menu/scan-image", tags=["staff", "manager"], response_model=MenuScanResponse)
+@limiter.limit("5/minute")
 async def scan_menu_endpoint(
+    request: Request,
     file: UploadFile = File(...),
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await scan_menu_image(file, credentials.credentials)
 
 @app.patch("/staff/menu/{item_id}", tags=["staff", "manager"])
+@limiter.limit("20/minute")
 async def update_menu_item_endpoint(
+    request: Request,
     item_id: str,
     update_data: UpdateMenuItemSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
@@ -234,21 +285,27 @@ async def update_menu_item_endpoint(
     return await update_menu_item(item_id, update_data, credentials.credentials)
 
 @app.delete("/staff/menu/{item_id}", tags=["staff", "manager"])
+@limiter.limit("20/minute")
 async def delete_menu_item_endpoint(
+    request: Request,
     item_id: str,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await delete_menu_item(item_id, credentials.credentials)
 
 @app.get("/staff/orders", tags=["staff", "manager"])
+@limiter.limit("60/minute")
 async def get_staff_orders_endpoint(
+    request: Request,
     status: str = "PAID",
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await get_stall_orders(credentials.credentials, status_filter=status)
 
 @app.patch("/staff/orders/{order_id}/status", tags=["staff", "manager"])
+@limiter.limit("30/minute")
 async def update_order_status_endpoint(
+    request: Request,
     order_id: str,
     status_data: UpdateOrderStatusSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
@@ -256,20 +313,26 @@ async def update_order_status_endpoint(
     return await update_order_status_staff(order_id, status_data, credentials.credentials)
 
 @app.post("/staff/orders/verify-pickup", tags=["staff", "manager"])
+@limiter.limit("100/minute")
 async def verify_pickup_endpoint(
+    request: Request,
     verify_data: VerifyPickupSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await verify_order_pickup(verify_data, credentials.credentials)
 
 @app.get("/staff/resale/items", tags=["staff"])
+@limiter.limit("30/minute")
 async def get_staff_resale_items_endpoint(
+    request: Request,
     credentials: HTTPAuthorizationCredentials = Security(security)
 ):
     return await get_stall_resale_items(credentials.credentials)
 
 @app.patch("/staff/resale/{resale_id}/price", tags=["staff"])
+@limiter.limit("20/minute")
 async def update_resale_price_endpoint(
+    request: Request,
     resale_id: str,
     body: UpdateResalePriceSchema,
     credentials: HTTPAuthorizationCredentials = Security(security)
diff --git a/requirements.txt b/requirements.txt
index adda9c1..f182951 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,7 +8,10 @@ cffi==2.0.0
 charset-normalizer==3.4.4
 click==8.3.1
 cryptography==46.0.3
+Deprecated==1.3.1
+dnspython==2.8.0
 dotenv==0.9.9
+email-validator==2.3.0
 fastapi==0.127.0
 firebase_admin==7.1.0
 gcloud==0.18.3
@@ -35,8 +38,11 @@ httpx==0.28.1
 hyperframe==6.1.0
 idna==3.11
 jwcrypto==1.5.6
+limits==5.6.0
+MarkupSafe==3.0.3
 msgpack==1.1.2
 oauth2client==4.1.3
+packaging==26.0
 proto-plus==1.27.0
 protobuf==5.29.5
 pyasn1==0.6.2
@@ -48,14 +54,17 @@ pydantic_core==2.41.5
 PyJWT==2.10.1
 pyparsing==3.2.5
 python-dotenv==1.2.1
+python-http-client==3.3.7
 python-jwt==4.1.0
 python-multipart==0.0.21
 razorpay==2.0.0
 requests==2.32.5
 requests-toolbelt==0.10.1
 rsa==4.9.1
+sendgrid==6.12.5
 setuptools==80.9.0
 six==1.17.0
+slowapi==0.1.9
 starlette==0.50.0
 tqdm==4.67.1
 typing-inspection==0.4.2
@@ -63,6 +72,5 @@ typing_extensions==4.15.0
 uritemplate==4.2.0
 urllib3==2.6.3
 uvicorn==0.40.0
-email-validator
-sendgrid
-
+Werkzeug==3.1.5
+wrapt==2.1.1