Product Overview

Voicify is a text-to-speech iOS application built with SwiftUI. It converts text inputs into high-quality audio files using OpenAI's TTS API, provides AI text improvement features via GPT-4o, tracks usage statistics using Aptabase, and gates daily character limits via RevenueCat.

Technical Stack

• Frontend: Swift & SwiftUI (iOS 16.0+)
• Backend: Node.js Firebase Cloud Functions
• Database & Authentication: Firebase Auth
• AI Services: OpenAI TTS API (gpt-4o-mini-tts) & OpenAI GPT-4o
• Monetization: RevenueCat SDK
• Analytics: Aptabase

Libraries & Dependencies (Swift Package Manager)

• firebase-ios-sdk (Firebase Auth)
• purchases-ios-spm (RevenueCat)
• aptabase-swift (Privacy-first analytics tracking)

Core App Features

1. OpenAI Text-To-Speech

• Natural Voices: Convert text to audio using OpenAI's natural voice presets.
• Audio Controls: Native audio player with seek, play, and pause controls.
• Audio Export: Export generated audio files.

2. AI Text Enhancer

• Optimize Text: Clean, format, and improve text inputs via GPT-4o before generating speech.

3. Usage Controls & Subscriptions

• Daily Character Limits: Metadata in RevenueCat packages determines character limits (e.g. 5,000 for trial, 20,000 for premium).
• Discount Offering Paywall: Retarget returning users with a discounted subscription.

4. Secure API Layer & Analytics

• Firebase Functions Proxy: Keeps OpenAI API keys secure on the server side.
• Aptabase Analytics: Tracks custom user metrics and failures.
• Multi-Auth Sign-In: Google, Apple, and Email authentication options.