A highly secure and scalable Industrial IoT (IIoT) SaaS based on blockchain. InfiIoT has been hosted in the cloud and provides services over the Internet. All industrial and commercial customers can connect equipment regardless of their geographical location to the SaaS and monitor and control equipment over the internet in real-time very securely thanks to the blockchain. Data is encrypted during transmission and stored in immune chains of data that are highly resistant to cyberattacks. Furthermore, all signal commands are verified by multiple synchronized smart contracts to protect expensive equipment from cyberattacks. Moreover, InfiIoT provides a code-less Artificial intelligence (AI) engine for designing any data processing flow in a few minutes. Some applications are predictive maintenance, digital twin, energy and sustainability management, distributed energy resources management (e.g., Photovoltaic, battery energy storage, wind turbines), HVAC systems, EV charging, BMS/BAS.