Full-Stack Developer (Kotlin Multiplatform + SvelteKit) – App Takeover & Ongoing Maintenance

We are Stuck In The Riddle Ltd, an escape room operator. We have recently finished building Riddle Ramble, an interactive, city-based escape room game app where players visit real-world waypoints to solve puzzles. The application is completely built and fully deployed, but our original development agency is winding down their operations. We are looking for a reliable, long-term freelance developer (or a tight-knit duo) to inherit the codebase, conduct a thorough initial code review, and handle ongoing maintenance, bug fixes, and future feature development. The Tech StackMobile Application: Kotlin Multiplatform (KMP) deploying to iOS and Android. Web Application (Creator Admin Dashboard): SvelteKit / JavaScript. Backend & Database: Firebase (Blaze Pay-As-You-Go Plan, utilizing Firestore, Authentication, and Cloud Functions). Hosting: Firebase Hosting (for the web app) and custom domain routing via GoDaddy. Infrastructure: Fully controlled under our own Google Cloud Organization workspace. Key Responsibilities Initial Code Review & Audit: Inherit the existing codebase from our GitHub repositories, set up a local development environment, and audit the code for stability and cleanliness. Onboarding & Configuration: Wire a local development/staging Firebase environment so updates can be safely tested before hitting the live production app. General Maintenance & Optimization: Act as our on-call developer to handle unexpected server issues, minor bugs, and OS-level update requirements (iOS/Android compliance). Future Feature Evolution: Collaborate with the business owner to plan and build new puzzle mechanics or game features over time. Candidate Requirements Proven, referenceable experience deploying live production apps using Kotlin Multiplatform (KMP). Strong proficiency in Svelte / SvelteKit and JavaScript for web applications. Production-level experience managing Firebase architecture (Firestore, Cloud Functions, Security Rules). Comfortable inheriting existing code without immediately demanding a full rewrite. Excellent communication skills in English.