Precision healthcare relies upon ubiquitous biofeedback to optimize therapy individually for nuanced and dynamic needs. However, grand challenges reside in the lack of soft, highly personalizable monitors that are scalable in manufacturing and reversibly interchangeable upon the evolution of needs. Herein, a customizable soft wearable platform is presented that can seamlessly integrate diverse functional modules, including physical and biochemical sensors, stimulators, and energy storage devices, tailored to various health monitoring scenarios, while can self-repair after certain mechanical damage. The platform supports versatile physiological sensing and therapeutic intervention due to its compatibility with wide-ranging functional nanomaterials. A bilayer microporous foam embedded in the gel improves sweat management for comfortable and reliable on-body biomarker monitoring. Furthermore, flexible self-healing zinc-air batteries using ion gel electrolytes provide opportunities for self-powered, closed-loop systems. On-body demonstrations validate the platform's capability to monitor physiological and metabolic states under real-world conditions. This work provides a scalable and adaptable materials-based solution for real-time personalized health monitoring, advancing wearable bioelectronics to meet evolving healthcare demands.