<![CDATA[Indonesian sub-national e-government portals are often delivered by vendors as completed systems without documentation, leaving local governments unable to maintain or further develop them safely. The Bekasi Keren portal (kotabekasikeren.com) represented this situation. An initial evaluation involving 52 city residents using the WebQual 4.0 framework produced a Grand Mean of 3.210, indicating Moderate quality across all 15 indicators. Importance–Performance Analysis (IPA) identified six indicators in Quadrant I, representing high-priority aspects requiring immediate improvement. Rather than proposing recommendations alone, this study reconstructed the portal based on those findings. The redesigned system was developed using Firebase Cloud Functions (Express.js), Google Cloud Firestore, and a Bootstrap 5 Multi-Page Application frontend to minimize loading overhead on low-end Android devices. Two interaction features absent from the original portal were introduced: a one-tap reaction mechanism secured with SHA-256 session hashing (NIST FIPS 180-4) to ensure idempotency, and a public comment system allowing submissions without account registration through IP-based rate limiting and administrator moderation. Functional testing confirmed that all 17 test scenarios passed successfully. A post-deployment evaluation involving 62 residents recorded a Grand Mean of 4.374 (Very High), representing a 36.3% improvement over the initial assessment. Usability increased by 1.230 points, Information Quality by 1.067, and Service Interaction Quality by 1.195. The largest improvement occurred in SI1 (Ease of Providing Feedback), which increased by 1.456 points and moved out of Quadrant I. These findings demonstrate that integrating Derived IPA with Prototyping provides an effective and practical approach for improving G2C portals in resource-constrained Indonesian local governments. ]]>
