Introduction. Delayed emergency recognition, limited first aid knowledge, communication difficulties, and barriers to ambulance access may hinder timely prehospital care. This study aimed to develop and preliminarily evaluate a web-based emergency response platform for prehospital first aid. Method. A research and development study guided by the ADDIE framework included needs analysis, platform design and development, expert validation, revision, and preliminary user evaluation. Needs were identified through literature review and focus group discussion. The platform integrated first aid education, emergency communication, location sharing, and ambulance activation. Content and media were assessed by experts, followed by community evaluation of application quality and technology acceptance. Result & Analysis. Needs assessment identified first aid information, emergency communication, location sharing, and ambulance access as key requirements. The platform included eleven educational modules covering emergency preparedness, victim assessment, cardiopulmonary resuscitation, medical emergencies, trauma and bleeding, burns, poisoning, disaster preparedness, home safety, road safety, and emergency activation. Expert and community evaluations showed favorable content, media, application-quality, and technology-acceptance ratings. Discussion. The platform demonstrated promising preliminary feasibility and acceptance as a digital approach to supporting community first aid and prehospital emergency access. Further real-world evaluation is required to determine effects on emergency activation, first aid performance, prehospital response, and patient outcomes.