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

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.
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