<p>Soybean is an important crop, and its growth and metabolism are highly sensitive to cadmium (Cd) toxicity. The study aimed to synthesize green silver nanoparticles (Ag NPs) and evaluate their potential to mitigate Cd-induced toxicity in soybean, while also exploring the underlying mechanisms of action. Ag NPs were green-synthesized using soybean leaf extracts and characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDS). Soybean seedlings were exposed to Cd stress (75 mg L^− 1) and treated with the synthesized Ag NPs (100 mg L^− 1). Cd exposure significantly reduced biomass and chlorophyll content, elevated ABA accumulation by 1.3-fold, and suppressed antioxidant enzyme activities. Application of green-synthesized Ag NPs alleviated these effects by promoting growth, restoring antioxidant activity, and modulating metabolite profiles. Notably, levels of glutamate, serine, and valine increased, indicating improved nitrogen metabolism under Cd stress. Docking analysis demonstrated stable interactions between Ag NPs and antioxidant enzymes, with binding scores of − 5.56 for superoxide dismutase and − 3.85 for catalase, supporting their role in mitigating oxidative stress. The application of green-synthesized Ag NPs can effectively reduce Cd toxicity in soybean by boosting antioxidant defenses, modulating stress hormone levels, and supporting nitrogen-related metabolic processes. These findings highlight the promise of green nanotechnology as a sustainable approach to enhance crop resilience and optimize nutrient management in soils affected by Cd contamination.</p>