UNextDoor
An interactive mobile application enabling users to converse with an AI voice tutor to develop language fluency.
The Challenge
Understanding client pain points
Traditional language learning software focuses on vocabulary cards but lacks conversational execution. Developing a realistic conversation partner requires low-latency voice-to-text, context-aware AI parsing, and realistic audio synthesis on mobile devices.
The Solution
Engineering a modern solution
We developed native iOS and Android apps using React Native. We optimized backend routing with FastAPI, connecting OpenAI Whisper, GPT-4, and text-to-speech engines in a custom asynchronous pipeline. The application processes audio inputs, evaluates grammar mistakes, and responds under 800ms.
Key features built to perform
Realtime Voice Interaction
Direct speech dialog with AI companion. Captures audio waveforms, displays live text transcripts, and plays speech responses.
Dynamic Grammar Feedback
Provides contextual correction overlays on user inputs, outlining alternative phrasing and spelling errors.
The Technology Stack
Challenges & Engineering Decisions
Reduced audio packet transit overhead by utilizing native audio format recording on mobile and implementing direct websocket audio streams to FastAPI handlers.
Project Outcomes
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