PostAI – AI Social Media Caption Generator & Content Creator Flutter App (Android & iOS)

Description

PostAI — AI-Powered Social Media Content Creator

PostAI is a complete Flutter mobile app that uses AI (OpenAI GPT-4o & Google Gemini) to generate social media captions, viral hooks, hashtag research, content repurposing, A/B testing, brand voice training, and content calendar management — all optimized per platform.

Built with clean architecture, Riverpod state management, Firebase backend, and ready-to-publish monetization (RevenueCat + AdMob). Just add your API keys and launch.

Download Demo APK

Key Features

• AI Caption Generator — Generate platform-optimized captions for Instagram, TikTok, LinkedIn, and Twitter/X. Choose tone, content type, and niche. Multiple captions per generation.
• Viral Hook Writer — 5 scroll-stopping opening hooks per topic across 6 styles: Curiosity, Controversy, Value, Story, Question, Bold Claim.
• Hashtag Research — Tiered hashtag packs (Mega 10M+, Mid 500K–10M, Niche under 500K) with real tag recommendations per platform.
• Content Repurpose Engine — Paste one piece of content and instantly adapt it to feel 100% native on every platform.
• Brand Voice Training — Train the AI on your writing style from examples. Apply your unique brand voice to all future generations.
• A/B Caption Tester — Objectively score and compare two captions with detailed breakdowns on hook strength, clarity, CTA, platform fit, and engagement potential.
• Content Calendar — Plan and schedule posts with AI-generated content ideas. Monthly grid view with status tracking (draft, scheduled, posted).
• Caption Library — Save, favorite, search, and filter all your generated captions by platform.

Supported Platforms

• Instagram — Long-form captions, 25 hashtags, emoji-rich
• ▶️ TikTok — Short punchy captions, trending hooks
• LinkedIn — Professional storytelling, thought leadership
• Twitter / X — Under 280 chars, bold and opinionated

Dual AI Support

• OpenAI GPT-4o / GPT-4o-mini — Primary AI provider for high-quality generation
• Google Gemini — Secondary provider, switchable via Firebase Remote Config
• Hot-swap between providers without app update

Built-in Monetization

• RevenueCat — Subscription management (monthly/yearly) with premium entitlements
• AdMob — Banner and interstitial ads for free tier users
• Free Tier Limits — Configurable daily limits via Remote Config (5 captions, 3 hooks, 2 hashtags, 2 repurpose, 1 A/B test per day)
• Paywall Screen — Beautiful paywall with feature comparison

Authentication

• Email / Password registration & login
• Google Sign-In
• Apple Sign-In
• Forgot Password flow

Beautiful UI

• Warm coral-to-orange gradient brand identity
• Poppins typography throughout
• Full Dark Mode support with system preference detection
• Smooth animations (Lottie + Flutter Animate)
• Shimmer loading states on every async operation
• Illustrated empty states on all list screens
• Platform-colored badges, chips, and character counters

️ Tech Stack

• Flutter 3.24+ — Android & iOS from a single codebase
• Dart 3.5+ — Full sound null safety
• Riverpod 2.x — Reactive state management
• GoRouter — Declarative navigation with auth guards
• Firebase — Auth, Cloud Firestore, Remote Config, Cloud Messaging
• Dio — HTTP client for AI API calls
• Freezed — Immutable data models with JSON serialization
• Hive + SharedPreferences — Local storage
• Material 3 — Modern design system with custom theme extensions

What You Get

• Full Flutter source code (Android + iOS)
• Clean architecture with separation of concerns
• Offline HTML documentation with setup guide
• Firebase security rules included
• Step-by-step setup guide
• All AI prompt templates — fully customizable
• Ready for App Store and Play Store submission

⚡ Quick Setup

1. Create Firebase project (Auth + Firestore + Remote Config + FCM)
2. Add google-services.json and GoogleService-Info.plist
3. Set your OpenAI API key in Firebase Remote Config
4. Run flutter pub get and dart run build_runner build
5. Run the app — done!

Requirements

• Flutter SDK 3.24 or later
• Android Studio or VS Code
• Firebase project (Blaze plan recommended)
• OpenAI API key (GPT-4o access)
• Google Gemini API key (optional)
• RevenueCat account (for subscriptions)
• AdMob account (for ads)

Changelog

Version 1.0.0 — April 2026 (Initial Release)

• [NEW] AI caption generator with multi-platform support (Instagram, TikTok, LinkedIn, Twitter/X)
• [NEW] Viral hook writer with 6 hook styles
• [NEW] Tiered hashtag research (mega, mid, niche)
• [NEW] Cross-platform content repurpose engine
• [NEW] Brand voice training from writing samples
• [NEW] A/B caption testing with objective scoring
• [NEW] Content calendar with AI-generated ideas
• [NEW] Caption library with favorites, search, and platform filter
• [NEW] Firebase Auth (Email, Google, Apple Sign-In)
• [NEW] RevenueCat subscription integration
• [NEW] AdMob banner and interstitial ads
• [NEW] Full dark mode support
• [NEW] Push notifications via FCM + local reminders
• [NEW] Dual AI support: OpenAI GPT-4o + Google Gemini

Support

We’re here to help you get up and running. Reach out anytime:

• Email: devsnack26@gmail.com
• WhatsApp: +855 967 413 911

We typically respond within 24 hours. When reporting issues, please include your Flutter version and any error messages or screenshots.

PostAI — Create. Post. Grow.

PostAI is a Flutter mobile app for Android and iOS that helps users create social media captions and post ideas with AI. Users enter a topic, product, image, or prompt, and the app generates draft captions, hashtags, and content suggestions that can be edited before posting. It is intended for small business owners, marketers, influencers, creators, and anyone who regularly writes social posts but wants help getting started or producing variations quickly. The product is designed for use across common social media platforms.