Electrochemical sensing devices rely heavily on the performance of their core components, particularly the electrodes. Common electrode materials include metals, such as platinum, gold, and Ag/AgCl, as well as various carbon-based materials. Alongside electrodes, insulators are crucial components in electrochemical devices. Insulators are used to delineate electrode areas to ensure reproducible outputs and prevent unintended contact between the solution and nonactive parts, such as leads. In microfabricated electrochemical sensing devices, both electrodes and insulators are patterned on substrates, such as glass, silicon, polymer, and paper. Consequently, microscopic electrochemical sensing devices are fabricated using techniques distinct from those used for conventional macroscopic devices, often employing batch fabrication of multiple sensor chips on a single substrate. Representative device fabrication methods can be broadly classified into thin-film techniques, such as photolithography and electron beam lithography, and thick-film techniques, such as screen printing and inkjet printing. Carbon electrodes can also be fabricated via pyrolysis of photoresist patterns and direct laser writing. These microfabricated electrochemical sensors are often integrated with microfluidics to process solutions of small volumes. For creating flow channels and reaction chambers, techniques such as replica molding and three-dimensional (3D) printing are employed. To fabricate biosensors, receptor biomolecules, such as enzymes, antibodies, and DNA, are immobilized at sensing sites using various approaches, including physisorption, covalent bonding, bioaffinity bonding, and entrapment.