Senior iOS Audio Engineer Needed to Fix / Rebuild Meditation App Audio Engine

Summary We have an iOS meditation app already built and in TestFlight. The design is complete, the app exists, and the ElevenLabs workflow is already integrated. However, the current audio experience is not launch-ready. We need a senior iOS audio engineer to audit the existing implementation and either fix or rebuild the iOS audio/session engine so the app delivers a seamless meditation experience. This is not a basic audio player project. We need someone with deep iOS audio experience who can handle real-time background music, prerecorded narration, AI-generated narration, smooth transitions, pause/resume, and offline replay. The Experience We Need -When the user starts a meditation: --Background music should begin immediately --A prerecorded intro should begin within seconds --The personalized ElevenLabs narration should be generated while the session is already beginning --The transition between prerecorded narration and AI-generated narration must feel seamless --The user should not be able to tell which parts are prerecorded and which parts are AI-generated --The full completed meditation should be saved for offline replay Pause and resume must work reliably Right now, the app generates everything before playback begins, which can take several minutes. That is not acceptable for the product experience. Current State: -iOS app is already built and available in TestFlight -Design is complete -ElevenLabs workflow is already built -Prerecorded audio files already exist -Current developer is available to explain the codebase -We prefer to salvage/fix the existing app if possible -However, we are open to replacing the audio engine if that is the correct technical path Scope of Work Milestone 1: Technical Audit -Review the existing iOS app/audio implementation and determine: -How audio is currently being generated, loaded, played, and cached -Why the current experience is not working -Whether the existing audio architecture can be fixed -Whether the UI/app can remain while the audio engine is replaced -What changes are required to make the app launch-ready Milestone 2: Fix or Rebuild iOS Audio Engine -Implement a production-grade iOS audio/session engine that supports: -Immediate background music playback -Smooth integration of prerecorded narration and AI-generated narration -Seamless transitions with no obvious gaps -Reliable timing and session flow -Pause/resume -Offline replay after a meditation has been fully generated -Stable playback across screen lock, background mode, AirPods/Bluetooth, and interruptions Required Experience Please apply only if you have real experience with: -iOS audio systems -AVFoundation -AVAudioSession -AVAudioEngine or equivalent audio mixing architecture -Background audio playback -Mixing voice over background music -Audio interruptions and route changes -Offline audio caching and replay -Session-based or long-form audio apps -Swift / native iOS development Experience with podcast, audiobook, meditation, sleep, wellness, music, or streaming audio apps is strongly preferred. Important Technical Requirements You should be comfortable explaining how you would handle: -Background music starting instantly -Prerecorded narration beginning while AI narration is still being generated -Buffering or preparing generated audio without blocking the start of the session -Smooth transitions between prerecorded and generated narration -Ducking/mixing music under voice -Pause/resume across a multi-part session -Saving a completed generated session for offline replay -Recovering gracefully from errors or interruptions Do Not Apply If Please do not apply if: -You think this can be solved with a simple AVAudioPlayer implementation -You have never shipped a serious iOS audio app -You cannot explain how to handle audio session interruptions and route changes -You do not have experience with background audio or offline replay -You are primarily a general mobile developer without deep audio experience Application Questions Please answer these in your application: -Describe the most technically complex iOS audio app you have worked on. -Have you built an app that mixes background music with voice narration? Explain. -How would you approach starting music immediately while AI-generated narration is still being prepared? -Have you used AVAudioEngine, AVAudioSession, MPNowPlayingInfoCenter, or background audio modes in production? -How would you decide whether to fix the current audio engine or replace it? -Have you built offline replay/caching for generated or downloaded audio? -Are you comfortable working with an existing codebase and coordinating with the previous developer for handoff? Ideal Candidate: The ideal candidate is a senior iOS audio engineer who can calmly walk into an existing TestFlight app, diagnose what is wrong, and create a reliable, polished, launch-ready meditation audio experience. We are not looking for someone to redesign the app. We are looking for someone to fix the iOS audio experience and make the product feel seamless, calm, and professional.