<![CDATA[Manual booking and technician scheduling at Emel Service, an AC maintenance micro-enterprise, frequently caused overlapping assignments and difficulty tracing customer repair histories. This study develops a web-based booking and scheduling application that applies the Earliest Due Date (EDD) rule, combined with a slot-locking mechanism, to order technician assignments by the earliest customer-selected appointment slot. The system was built using the Prototyping method with the Laravel framework, MySQL, and Docker, and analysed with PIECES and UML. The EDD logic is illustrated through a worked scheduling example that compares the as-received order with the EDD order using completion time and lateness. Functional testing with Black Box Testing covered six core business scenarios, all of which passed (valid), while User Acceptance Testing with the business owner confirmed that the application fits the partner's daily operational workflow. The scientific contribution of this study is a concrete reference design that integrates the EDD rule with multi-session slot locking and structured WhatsApp confirmation drafts for service-sector micro, small, and medium enterprises (MSMEs). The system replaces manual record-keeping with a structured relational database, prevents double-booked slots at the design level, and accelerates order confirmation. This study is limited to functional and single-stakeholder acceptance evaluation in a localhost environment; comparative operational measurement over time is identified as future work.]]>
