<![CDATA[Fast and accurate blood donor availability is a vital factor in emergency healthcare services, especially in archipelago and remote regions such as Larantuka District, East Flores Regency. Limitations of conventional donor search methods relying on social media or group messaging often suffer from response delays and location inaccuracies. This study aims to design and implement a location-based nearby volunteer blood donor search system utilizing the Haversine algorithm. The system was developed as a web and Android mobile application using the Laravel framework, Tailwind CSS, Alpine.js, and Capacitor, integrated with Google Maps API and real-time notifications via Laravel Reverb. Functional testing using black-box testing achieved a 100% pass rate. Usability testing using the System Usability Scale (SUS) among 10 respondents yielded an average score of 79.25 (Grade B / Good-Acceptable). Effectiveness testing demonstrated an average distance calculation error of 1.88% (below the 10% error threshold), a donor search success rate of 95%, and notification delivery accuracy of 87.5%. The results confirm that the developed system effectively assists health facilities in finding suitable blood donors quickly, accurately, and seamlessly. ABSTRAK Ketersediaan darah yang cepat dan akurat merupakan faktor vital dalam pelayanan kesehatan darurat, khususnya di wilayah kepulauan dan daerah 3T seperti Kecamatan Larantuka, Kabupaten Flores Timur. Keterbatasan sistem pencarian pendonor konvensional yang masih mengandalkan media sosial atau pesan berantai sering kali mengalami kendala berupa keterlambatan respon dan ketidakakuratan lokasi. Penelitian ini bertujuan untuk merancang dan mengimplementasikan sistem pencarian relawan pendonor terdekat berbasis lokasi menggunakan algoritma Haversine. Sistem dibangun berbasis web dan mobile Android menggunakan framework Laravel, Tailwind CSS, Alpine.js, serta Capacitor, terintegrasi dengan Google Maps API dan sistem notifikasi real-time via Laravel Reverb. Pengujian fungsionalitas menggunakan black-box testing menunjukkan tingkat keberhasilan 100%. Pengujian usability menggunakan System Usability Scale (SUS) terhadap 10 responden menghasilkan skor rata-rata 79,25 (Grade B / Good-Acceptable). Pengujian efektivitas menunjukkan rata-rata selisih perhitungan jarak sebesar 1,88% (di bawah batas error 10%), tingkat keberhasilan pencarian relawan sebesar 95%, dan ketepatan penyampaian notifikasi sebesar 87,5%. Hasil penelitian membuktikan bahwa sistem ini efektif dalam membantu fasilitas kesehatan menemukan pendonor darah yang sesuai secara cepat, presisi, dan terintegrasi. ]]>
