The demand for efficient indoor logistics has driven interest in autonomous and semi-autonomous mobile robotic systems. These systems are useful for transporting items in structured spaces like offices, hospitals, and academic institutions. This paper presents LineCourier, a semi-autonomous mobile robot built for indoor file delivery. The system combines embedded control, line navigation, obstacle detection, and a web-based interface for task control and monitoring. It uses infrared (IR) sensors to follow a black line and an ultrasonic sensor to detect obstacles in its path. An ESP32 microcontroller manages the robot’s functions. It reads sensor data and controls motion through an L298N motor driver. A MERN stack-based web application provides real-time monitoring. It shows the robot’s current position, route, and delivery status. Users can assign tasks and receive live feedback remotely. The system was tested through 300 delivery runs over five separate trials. Each run was assessed for line tracking, obstacle handling, and task completion. A run was considered failed if the robot left the line, did not complete the task, or needed manual help. The robot achieved an average success rate of 96.67%, showing stable and reliable performance. The architecture is modular, which allows easy expansion and future upgrades. The results prove that LineCourier is a reliable solution for indoor logistics and can support smart office automation and service robotics.