Conventional doors have gotten little attention for a number of reasons, including the need for a unique key for each door, the requirement of specialized equipment to duplicate keys, the difficulty to determine who opened the door, and the absence of alternatives to utilizing the traditional key. Apart from that, standard locks are subject to lock picking tools, tools that reach under/over the door frame to reach the door handle, and bump keys, which utilize force to set the lock pins and open the door. This paper develops a secure Internet of Things Smart Door Lock System (IoT-SDL) that can unlock door without keys or other physical tools. Installing and initializing the IoT-SDL system requires inserting the home’s WIFI SSID and password into the Raspberry Pi’s WIFI access point and providing internet connectivity. After installation, users may be configured and enabled IoT-SDL capabilities using a web interface. The IoT-SDL system includes a touchscreen keypad and an RFID scanner that are used to unlock the door if the user chooses to activate the two-factor authentication function. The results showed the ability of the IoT-SDL system to remember who pushed the door unlock button, so it is possible to exactly know who has been in the space. Additionally, the user had the ability to generate temporary PIN codes that are valid for a predetermined amount of time and are intended for reliable guests to enter on the touchscreen keypad of the IoT-SDL in order to open the door. The IoT-SDL system includes a number of additional options that can be used to personalize the way the door functions due to the essential property that the door should be used to serve its users rather than the other way around. The user had the ability to remotely open the door with the push of a button after they have used the interfaces that are provided to them. The access was possible to any and all of the data that the IoT-SDL has collected by making use of the different application program interfaces.