with safety in mind, markedly decrease the risk of exposure to hazardous substances such as payload linkers in ADC manufacturing. In 2022, our group successfully produced cysteineconjugated ADCs using FMR, marking the first report of FMR-based ADC synthesis . This achievement entailed using clinically relevant antibodies and drug linkers and optimizing mixer types, reaction times, and diameters to produce ADCs without significant aggregation. However, there is a report wherein site-specific ADC production or affinity-guided protein modification could not be achieved in continuous mode. There were initial concerns that the rapid mixing approach could lead to unintended nonspecific conjugation or compromise the quality of the protein product. However, given its notably high affinity for antibodies at the nanomolar level, we anticipated that the AJICAP-M conjugation method would be compatible with the flow kinetic mixing mode. This high affinity is expected to mitigate the risk of nonspecific reactions and maintain the integrity of the protein. We used a V-shaped stainless-steel mixer with an inner diameter of 0.25 mm and a cascade-dual-mode mixing system (Figure ). The critical step in the AJICAP-M conjugation process was identified as the initial antibody modification by the peptide reagent, which occurred primarily in mixer-1 and reactor-1. To facilitate this, we employed an 8meter reactor tube for a reaction time of 3 min. Our design focused on flash chemistry to optimize mixing efficiency, characterized by rapid mixing at high flow rates. This strategy led to the successful replication of site-specific ADC production, comparable to that achieved in the batch mode. Notably, this method enables rapid site-specific ADC synthesis within 5 min, presenting a significant advantage for efficient future ADC manufacturing.