Fullstack

Friendly

Cross-platform student productivity app with AI lecture transcription, smart schedule management, PDF analysis, GPA tracking, and school-verified community. React Native (Expo) + Node.js backend with Firebase and OpenAI.

My Role

Backend & Frontend Developer

Core Stack

React Native, Expo, Node.js, Express, Firebase, OpenAI

Timeline

2025.09 — 2025.12

Live Project

friendlykr.com

The Challenge

The core problem

Students juggle separate tools for lecture recording, schedules, documents, GPA, and community. Nothing is in one place; context is scattered and sync is manual.

Product vision

One cross-platform app that unifies lecture capture, schedule management, document analysis, GPA tracking, and school-verified community—with real-time AI and cloud sync.

What I owned

Backend and frontend: Node.js + Express API, Firebase (Auth, Firestore, Storage), and React Native (Expo) with NativeWind. Shipped real-time Whisper transcription, GPT-4o-mini summaries and action items, GPT-4o Vision for schedule extraction from images, PDF analysis and chatbot, and optional Google Calendar and Drive backup. 50+ reusable components and 100+ API endpoints.

Results

Single app for lecture, schedule, PDF, GPA, and community. Live transcription and sync; image-based schedule import; PDF-aware chatbot. Available at friendlykr.com.

Design system & UI

NativeWind (Tailwind) for consistent styling across iOS, Android, and Web. Color system for primary actions, status, and accessibility; 50+ reusable components with React Context for global state.

Typography

Inter Bold

Inter Medium

Inter Regular

Colors

Primary Blue

#3B82F6

Secondary Gray

#6B7280

Success Green

#10B981

Warning

#F59E0B

Error Red

#EF4444

Background

#F9FAFB

Design system visual

System architecture

Modular service-layer backend with real-time Firestore; cross-platform app with Expo Router and NativeWind.

Frontend
Backend & API
Integrations

Frontend

  • React Native 0.81.5 + Expo SDK 54, Expo Router (file-based routing)
  • TypeScript, NativeWind 4.2.1, React Context API
  • PDF.js viewer, React Native Reanimated

Backend & API

  • Node.js + Express 5.1, Firebase Admin SDK, Firestore, Firebase Storage
  • 100+ RESTful API endpoints, PM2 process management
  • Multer for uploads, daily Google Drive autobackup

Integrations

  • OpenAI: GPT-4o-mini, GPT-3.5-turbo, Whisper, Vision
  • Firebase Auth, Google Calendar API, Google Drive API
  • PDF-Parse for text extraction
Lecture recording and transcription flow
Feature 01

AI-powered lecture transcription

Live recording with real-time Whisper transcription, GPT-4o-mini summaries and action items, and a lecture-aware chatbot with conversation history.

WhisperGPT-4o-miniFirestore
Schedule and PDF analysis
Feature 02

Smart schedule & PDF analysis

Upload schedule images for GPT-4o Vision extraction and drag-and-drop calendar editing; upload PDFs for text extraction and PDF-aware chatbot with page-level context.

GPT-4o VisionPDF.jsGoogle Calendar

Impact & results

Friendly delivers an AI-powered productivity platform with real-time transcription, document analysis, and cross-platform support. Modular architecture and autobackup ensure reliability and maintainability.

100+

API endpoints

4

OpenAI models integrated

50+

UI components

iOS · Android · Web

Cross-platform

Reflection

I’d invest earlier in E2E tests for critical paths (recording → transcription, schedule import, PDF chat) and in clearer offline/conflict handling. I learned a lot about coordinating Whisper, Vision, and Firestore in a single product surface.