The rapid growth of India’s quick-commerce and online grocery segment has intensified competition among major platforms — BigBasket, Blinkit, Swiggy Instamart, and Zepto. Customer retention has emerged as a critical determinant of long-term profitability in a market characterised by low switching costs and aggressive price competition. This study examines and compares the retention strategies of these four platforms in Bangalore. Employing a mixed-methods design, primary data were collected through a structured questionnaire administered to 320 respondents, supplemented by platform analytics, loyalty programme documentation, and managerial interviews, evaluating retention across six dimensions via a novel Customer Retention Quality Index (CRQI). Findings reveal that BigBasket leads in loyalty depth and assortment breadth, while Blinkit and Zepto dominate on speed and Gen-Z appeal; Swiggy Instamart leverages ecosystem lock-in through its super-app strategy. The study identifies significant gaps in postpurchase engagement, grievance resolution, and hyper-local personalisation across all platforms, and presents actionable recommendations for platform managers, investors, and policymakers, contributing a multi-dimensional benchmarking framework applicable to emerging quick-commerce markets globally.