A modular IoT logger that can turn any sensor to a connected data source. It comprises of a base board and a set of expansion shields that can support practically any commercial sensor out-of-the-box. The logger provides support for all popular digital and analogue interfaces at once, such as SDI-12, Modbus RTU, Analogue, 4-20mA, Pulse Counters, allowing to build and scale custom IoT applications at a fraction of time compared to standard approaches. It can be used both as a development platform for new IoT projects at pilot phases, but also as a field-ready product for large-scale deployments.