DELIVERY-seq is a platform for high-throughput screening of lipid nanoparticles (LNPs), using uniquely barcoded mRNA molecules that act as both therapeutic payload and molecular identifier. These barcodes enable tracing of distinct LNP formulations pooled in a single experiment, avoiding DNA co-encapsulation that can distort delivery efficiency. DELIVERY-seq enables sensitive, single-cell resolution analysis of delivery, expression, and mRNA degradation. ConcepTT funding will support key proof-of-concept activities: validating quantification accuracy, optimizing single-cell workflows, benchmarking against DNA barcoding, and engaging industry. This will de-risk the technology and pave the way for commercialization. DELIVERY-seq reduces animal use and cost, while accelerating development of next-generation mRNA therapeutics.