Pengembangan Sistem Pembayaran Sewa Indekos Berbasis Android dan Web Terintegrasi Payment Gateway dengan Pengamanan AES-256

Manual rent administration at Kost Bellva requires the owner to record transactions in a ledger and verify transfer receipts individually, creating risks of recording errors and data loss. This study develops an Android and web rent payment system integrating a payment gateway and AES-256 encryption for sensitive payment information. This study adopted a case study approach, with data collected through observation and interviews with the boarding house owner. Development comprised problem identification, requirements analysis, system and database design, implementation, and functional testing. The prototype uses Flutter and Dart for the tenant application, Next.js for the administrator dashboard, Supabase PostgreSQL for centralized data storage, and Midtrans for payment processing and status notifications. The resulting system supports room and tenant management, billing, digital payments, payment history, and financial summaries, while sensitive payment instructions are encrypted before storage. All 34 documented black box test scenarios produced results consistent with their expected outputs. These findings indicate that the prototype meets the tested functional requirements and provides an integrated rent payment management workflow for the Kost Bellva case study.