diff --git a/.env b/.env
new file mode 100644
index 0000000..c7f72ad
--- /dev/null
+++ b/.env
@@ -0,0 +1 @@
+WHITELISTED_IPS = 52.88.246.140,52.10.220.50,54.190.46.191,52.43.82.110,127.0.0.1
\ No newline at end of file
diff --git a/app.py b/app.py
index e69de29..50b6f8c 100644
--- a/app.py
+++ b/app.py
@@ -0,0 +1,57 @@
+import logging
+import uvicorn
+
+from database import engine, Base
+from dotenv import load_dotenv
+from fastapi import FastAPI, Request, status
+from fastapi.responses import JSONResponse
+from loggerino import timestamp_log_config
+from os import getenv
+from schemas import SMSMessage
+from service import inbound_sms_handler, retrieve_sms_messages_by_phone_number
+from sqlalchemy.orm import Session, joinedload
+from uvicorn.config import LOGGING_CONFIG
+
+
+# Create instance of FastAPI
+app = FastAPI()
+
+# Load dotenv file (.env)
+load_dotenv()
+
+# Load custom logger format
+logger = logging.getLogger("uvicorn.error")
+
+# Create tables (if they don't exist)
+Base.metadata.create_all(bind=engine)
+
+# Load whitelisted IPs
+WHITELISTED_IPS = getenv("WHITELISTED_IPS").split(',')
+
+
+@app.middleware("http")
+async def validate_ip(request: Request, call_next):
+    ip = str(request.headers.get("x-forwarded-for", str(request.client.host)))
+
+    if ip not in WHITELISTED_IPS:
+        data = {"message": f"IP {ip} is not allowed to access this resource."}
+        return JSONResponse(status_code=status.HTTP_400_BAD_REQUEST, content=data)
+
+    return await call_next(request)
+
+
+@app.post("/sms-message", status_code=status.HTTP_200_OK)
+async def receive_sms_message(message: SMSMessage):
+    inbound_sms_handler(message)
+
+
+@app.get('/sms-message/{number}')
+def get_sms_messages_by_phone_number(number: str, limit: int = 10, page: int = 1):
+    contact = retrieve_sms_messages_by_phone_number(number, limit, page)
+    return {'status': 'success', 'results': len(contact.messages), 'response': contact}
+
+
+if __name__ == "__main__":
+    uvicorn.run(
+        app, host="0.0.0.0", port=8000, log_config=timestamp_log_config(LOGGING_CONFIG)
+    )
diff --git a/dtos.py b/dtos.py
new file mode 100644
index 0000000..523f32b
--- /dev/null
+++ b/dtos.py
@@ -0,0 +1,55 @@
+from models import SMSMessage as SMSDBMessage, SMSContact, SMSCost, SMSMetadata
+from schemas import SMSMessage
+
+
+def to_db(message: SMSMessage) -> SMSContact:
+    payload = message.data.attributes
+
+    sms_metadata = SMSMetadata()
+    sms_metadata.message_callback_url = payload.message_callback_url
+    sms_metadata.message_encoding = payload.message_encoding
+    sms_metadata.message_type = payload.message_type
+    sms_metadata.status = payload.status
+
+    sms_cost = SMSCost()
+    sms_cost.amount_display = payload.amount_display
+    sms_cost.amount_nanodollars = payload.amount_nanodollars
+
+    sms_message = SMSDBMessage()
+    sms_message.from_number = payload.from_number
+    sms_message.direction = payload.direction
+    sms_message.is_mms = payload.is_mms
+    sms_message.message = payload.message
+    sms_message.timestamp = payload.timestamp
+    sms_message.cost = sms_cost
+    sms_message.sms_metadata = sms_metadata
+
+    sms_contact = SMSContact()
+    sms_contact.phone_number = payload.to_number
+    sms_contact.messages = [sms_message]
+    return sms_contact
+
+
+def to_db_existing_contact(message: SMSMessage) -> SMSDBMessage:
+    payload = message.data.attributes
+
+    sms_metadata = SMSMetadata()
+    sms_metadata.message_callback_url = payload.message_callback_url
+    sms_metadata.message_encoding = payload.message_encoding
+    sms_metadata.message_type = payload.message_type
+    sms_metadata.status = payload.status
+
+    sms_cost = SMSCost()
+    sms_cost.amount_display = payload.amount_display
+    sms_cost.amount_nanodollars = payload.amount_nanodollars
+
+    sms_message = SMSDBMessage()
+    sms_message.from_number = payload.from_number
+    sms_message.direction = payload.direction
+    sms_message.is_mms = payload.is_mms
+    sms_message.message = payload.message
+    sms_message.timestamp = payload.timestamp
+    sms_message.cost = sms_cost
+    sms_message.sms_metadata = sms_metadata
+
+    return sms_message
\ No newline at end of file
diff --git a/flowsms.db b/flowsms.db
new file mode 100644
index 0000000..43c5dbc
Binary files /dev/null and b/flowsms.db differ
diff --git a/loggerino.py b/loggerino.py
new file mode 100644
index 0000000..14bfae5
--- /dev/null
+++ b/loggerino.py
@@ -0,0 +1,13 @@
+from typing import Any, Dict
+
+
+def timestamp_log_config(uvicorn_log_config: Dict[str, Any]) -> Dict[str, Any]:
+    datefmt = "%d-%m-%Y %H:%M:%S"
+    formatters = uvicorn_log_config["formatters"]
+    formatters["default"]["fmt"] = "%(levelprefix)s [%(asctime)s] %(message)s"
+    formatters["access"]["fmt"] = (
+        '%(levelprefix)s [%(asctime)s] %(client_addr)s - "%(request_line)s" %(status_code)s'
+    )
+    formatters["access"]["datefmt"] = datefmt
+    formatters["default"]["datefmt"] = datefmt
+    return uvicorn_log_config
diff --git a/models.py b/models.py
index 9e8c96a..834728c 100644
--- a/models.py
+++ b/models.py
@@ -9,10 +9,9 @@ from uuid import uuid4, UUID
 class SMSContact(Base):
     __tablename__ = 'contact'
     id: Mapped[UUID] = mapped_column(primary_key=True, default=uuid4)
-    phone_number = Column(String, nullable=False)
+    phone_number = Column(String, nullable=False, unique=True)
     messages: Mapped[List["SMSMessage"]] = relationship()
     created_at = Column(TIMESTAMP(timezone=True), nullable=False, server_default=func.now())
-    updated_at = Column(TIMESTAMP(timezone=True), default=None, onupdate=func.now())
 
 
 class SMSMessage(Base):
@@ -25,9 +24,8 @@ class SMSMessage(Base):
     message = Column(String, nullable=False)
     timestamp = Column(DateTime, nullable=False)
     cost: Mapped["SMSCost"] = relationship(back_populates="message")
-    metadata: Mapped["SMSMetadata"] = relationship(back_populates="message")
+    sms_metadata: Mapped["SMSMetadata"] = relationship(back_populates="message")
     created_at = Column(TIMESTAMP(timezone=True), nullable=False, server_default=func.now())
-    updated_at = Column(TIMESTAMP(timezone=True), default=None, onupdate=func.now())
 
 
 class SMSCost(Base):
@@ -38,7 +36,6 @@ class SMSCost(Base):
     message_id: Mapped[UUID] = mapped_column(ForeignKey("message.id"))
     message: Mapped["SMSMessage"] = relationship(back_populates="cost")
     created_at = Column(TIMESTAMP(timezone=True), nullable=False, server_default=func.now())
-    updated_at = Column(TIMESTAMP(timezone=True), default=None, onupdate=func.now())
 
 
 class SMSMetadata(Base):
@@ -49,6 +46,5 @@ class SMSMetadata(Base):
     message_type = Column(String, nullable=False)
     status = Column(String, nullable=False)
     message_id: Mapped[UUID] = mapped_column(ForeignKey("message.id"))
-    message: Mapped["SMSMessage"] = relationship(back_populates="metadata")   
+    message: Mapped["SMSMessage"] = relationship(back_populates="sms_metadata")   
     created_at = Column(TIMESTAMP(timezone=True), nullable=False, server_default=func.now())
-    updated_at = Column(TIMESTAMP(timezone=True), default=None, onupdate=func.now())
diff --git a/requirements.txt b/requirements.txt
index 878ea94..5950719 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,4 @@
 fastapi
 python-dotenv
 sqlalchemy
+uvicorn
diff --git a/service.py b/service.py
index e69de29..9219e44 100644
--- a/service.py
+++ b/service.py
@@ -0,0 +1,30 @@
+from database import get_db
+from dtos import to_db, to_db_existing_contact
+from models import SMSContact, SMSMessage as SMSDBMessage
+from schemas import SMSMessage
+from sqlalchemy.orm import joinedload
+
+
+def inbound_sms_handler(message: SMSMessage) -> None:
+    db = next(get_db())
+    payload = None
+
+    sms_contact_exists = db.query(SMSContact).filter(SMSContact.phone_number == message.data.attributes.to_number).first()
+    
+    if sms_contact_exists:
+        payload = to_db_existing_contact(message)
+        payload.to_number = sms_contact_exists.id
+    else:
+        payload = to_db(message)    
+    
+    db.add(payload)
+    db.commit()
+    db.refresh(payload)
+
+
+
+def retrieve_sms_messages_by_phone_number(number: str, limit: int , page: int) -> SMSContact:
+    db = next(get_db())
+    skip = (page - 1) * limit
+    messages = db.query(SMSContact).filter(SMSContact.phone_number == number).options(joinedload(SMSContact.messages)).limit(limit).offset(skip).first()
+    return messages