We present the most compact (4 cm3) time domain diffuse optical spectroscopy system, hosting 8 laser sources emitting at different wavelengths, a large area time-gated detector, and a time-to-digital converter. We tested the optode using standardized protocols, enlightening a high light harvesting capability and large penetration depth in detecting realistic optical inhomogeneities. We tested it also in vivo for the non- invasive assessment of blood parameters in a vascular occlusion test and for the detection of brain activation, demonstrating the optode capability to follow task-related hemodynamic changeseven through a single measurement, with no need for averaging or filtering as instead needed with most available systems. The optode is thus a good candidate for next generation home-monitoring devices, thanks to its good performances, small dimension and potential low-cost.