This thesis examines whether Instacart’s mid-2022 expansion of Supplemental Nutrition Assistance Program (SNAP) EBT payment in ten U.S. states affected SNAP recipients’ grocery purchasing behavior. It focuses on three key outcomes – total online grocery purchases, healthy grocery purchases, and healthy online grocery purchases – and considers differences between urban food deserts and non-desert areas. Using panel data from 2020 to 2024 covering 2,788 ZIP codes and employing difference-in-differences and triple-difference models, the analysis identifies the policy’s causal impacts. The results indicate that the SNAP EBT expansion significantly increased SNAP households’ online grocery purchases, including a notable rise in online purchases of healthy foods, with especially pronounced gains in urban food desert neighborhoods. In contrast, the overall purchase of healthy foods experienced only a modest uptick, suggesting that improved online access alone did not dramatically change total healthy consumption in the short term. These findings highlight the potential of online grocery platforms to enhance food access for low-income communities and inform policy discussions on leveraging technology to promote better nutrition.