This　study　comprehensively　investigates　hydrogen　production　from　green　ammonia　reforming,　including　synthesis　of　catalysts,　reactor　development,　process　integration,　and　techno-economic　analysis.　In-house　developed　Ru/La–Al2O3　pellet　catalyst　having　perovskite　structure　showed　high　catalytic　activity　of　2827　h−1　at　450　°C　and　stability　over　6700　h　at　550　°C,　exceeding　the　performance　of　the　majority　of　powder　catalysts　reported　in　the　literature.　A　scalable　12-faceted　reactor　adopting　the　as-produced　catalyst　was　designed　to　enhance　heat　transfer,　producing　over　66　L　min−1　of　hydrogen　with　state-of-the-art　ammonia　reforming　efficiency　of　83.6　%.　Near-zero　CO2　emission　of　hydrogen　extraction　from　green　ammonia　was　demonstrated　by-product　gas　recirculation　as　a　combustion　heat　source.　A　techno-economic　assessment　was　conducted　for　system　scales　from　10　kW　to　10　MW,　demonstrating　the　effect　of　reduced　minimum　hydrogen　selling　prices　from　7.03　USD　kg−1　at　small　modular　scales　to　3.98　USD　kg−1　at　larger　industrial　scales.　Sensitivity　analyses　indicate　that　hydrogen　selling　prices　may　reduce　even　further　(up　to　50　%).　The　suggested　hydrogen　production　route　from　green　NH3　demonstrates　superior　CO2　reduction　ranging　from　78　%　to　95　%　in　kg　CO2　(kg　H2)−1　compared　to　biomass　gasification　and　steam　methane　reforming.　These　findings　can　be　used　as　a　basis　for　following　economic　and　policy　studies　to　further　validate　the　effectiveness　of　the　suggested　system　and　process　for　H2　production　from　NH3.　©　2021