<![CDATA[Abstrak. Sistem layanan administrasi yang masih dilakukan secara manual kepada nasabah Koperasi Payana Mandiri, menimbulkan ketidakefektifan dalam pencatatan, pengelolaan data, serta pelaporan dan penyajian informasi. Artikel ini menyajikan model aplikasi simpan pinjam berbasis Web pada sisi administrator sistem, dikombinasikan dengan sistem berbasis mobile pada sisi pengguna sistem (nasabah dan pegawai perusahaan). Pengembangan sistem menggunakan metode Linear Sequential Model (LSM), sedangkan desain sistem menggunakan teknik pemodelan terstruktur. Sistem berbasis Web merupakan bagian utama sekaligus backend dari sistem aplikasi, yang dikembangkan dengan framework laravel. Pada bagian backend Website juga menyediakan API (Application Programming Interface) yang dapat diakses oleh mobile apps untuk sinkronisasi data pada mobile apps. Mobile apps sendiri dikembangkan dengan framework Flutter. Fungsi-fungsi yang diidentifikasi pada analisis kebutuhan berupa fitur manajemen data nasabah, data setoran dan penarikan tabungan, data peminjaman dan pembayaran angsuran, informasi simpanan, serta riwayat transaksi. Hasil uji Blackbox menunjukkan sistem telah berjalan sesuai dengan kebutuhan pengguna.Kata kunci: Aplikasi Simpan Pinjam; Berbasis Web; Berbasis Mobile; framework laravel; Framework Flutter Abstract. The administrative service system, which is still done manually for “Payana Mandiri” Union customers, creates ineffectiveness in recording, managing data, as well as reporting and presenting information. This article presents a Web-based savings and loan application model on the system administrator side, combined with a mobile-based system on the system user side (customers and company employees). The system development uses the Linear Sequential Model method, while the system design uses a structured modeling technique. Web-based system is the main part as well as the backend of the application system, which is developed with the laravel framework. On the backend, the website also provides an API (Application Programming Interface) which can be accessed by mobile apps for synchronizing data on mobile apps. Mobile apps themselves are developed with the Flutter framework. The functions identified in the needs analysis include customer data management features, savings deposit and withdrawal data, loan and installment payment data, deposit information, and transaction history. Blackbox testing results show the system has been running according to user needs.Keywords: Savings and Loan Application; Web-Based; Mobile-Based; Laravel Framework; Flutter Framework]]>
