Andy

Lullaby is an AI bedtime companion that turns your day into a personalized sleep story — built for adults who are exhausted but still wide awake at 2AM. The entire experience lives inside a single conversation. We built an AI agent system on Replit that tracks user intent through the chat and orchestrates everything behind the scenes — onboarding, daytime check-ins, voice customization, and nighttime story generation — so users never have to navigate between screens or modes. The UI dynamically adapts based on each response, surfacing buttons and flows only when needed. The result is something that feels less like an app and more like talking to someone who knows when to listen, when to ask, and when to start reading you a story. On the voice side, we used ElevenLabs' Voice Design API to let users customize and iterate on their preferred voice, Text-to-Speech (V3) for delivery, and emotional tags throughout to make the listening experience feel natural and warm. On Replit, we built a database for persistent user memory so Lullaby personalizes over time, integrated the ElevenLabs APIs, and shipped to TestFlight via App Store publishing. Android users can preview on web via Expo Go: https://lullaby-2026-hackathonmobile.replit.app

Submitted 9 Apr 2026