Garlic is one of the horticultural commodities with diverse benefits and high consumption. The challenge in improving the quality and production of garlic is the difficulty in determining suitable land, as garlic cannot thrive in just any location. The assessment of land suitability for garlic production is required to support the government's self-sufficiency program for garlic from 2030 to 2045. This study aims to develop the backend module of the Agro-ecological Land Suitability Assessment System for Garlic. The result of land assessment from this backend system will be visualized using mobile and web-based GIS applications. Different from other previous land suitability assessment systems, the determination of garlic land suitability in this system is based on twelve primary garlic growth requirements grouped into three factors: factors that are uncontrollable and uncorrectable, factors that can be corrected, and factors that can be controlled. The use cases implemented in this system include user registration, land suitability assessment, viewing land suitability assessment results on the map, viewing a list of previously assessed lands, viewing all lands assessed by users, viewing the history of a land's class, reading the glossary of garlic growth requirement's terms, viewing user profiles, logging in and out. The backend system resulted in a database with 16 tables and 37 Application Programming Interfaces, along with 1 scheduler, which has been successfully tested using black box testing methodology. [ABSTRACT FROM AUTHOR]