Back to works Case Study
AI IntegrationSaaS ProductReact & Tailwind

PostRewriter AI

AI-powered writing SaaS platform designed to instantly rewrite drafts into engaging content with multiple tone presets, integrated dark mode, and single-click Google authentication.

Visit Live Website
PostRewriter AI Interface Showcase

01 — Overview

Overview

a. AI-Powered Content Transformation

Social media managers and content creators often struggle to rewrite drafts for different platforms, adjust formatting, or shift tones quickly. Rewriting content manually across multiple social accounts is time-consuming and limits publication frequencies.

We built PostRewriter AI to resolve this bottleneck. The SaaS platform allows users to paste raw drafts, select a tone preset (such as Professional, Storytelling, or Casual), and generate copy tailored for social channels.

b. SaaS Platform Architecture

We designed a clean, decoupled architecture for this SaaS. The frontend is a React-powered Single Page Application (SPA) bundled via Vite and styled using Tailwind CSS. It communicates with a secure Node.js backend to handle API routing, session checks, and third-party API dispatches.

Authentication is delegated to Google OAuth via Firebase, providing a secure, passwordless login flow. Payment verification is handled through Stripe callbacks to manage user status changes.

Timeline Feb 2026 – Jun 2026
Role Full-Stack SaaS Development & AI Integration
Technologies
React 18Tailwind CSSViteNode.jsExpressOpenAI APIFirebase AuthStripe
Tools
VS CodeGitPostmanFigmaGoogle Cloud Console
Responsibilities
  • Developed a reactive single-page application frontend using React 18 and Tailwind CSS with light/dark theme toggling
  • Integrated OpenAI GPT models to process text rewrites based on selected tone prompts (Professional, Humble Brag, Storytelling, etc.)
  • Implemented Firebase Google Login ("Continue with Google") for frictionless user authentication and session management
  • Configured rate limiting and context length validation (300 words for free tier, 1,000 words for pro tier) on backend endpoints
  • Designed conversion-optimized pricing layouts and integrated payment processing pipelines
  • Built a live global generation counter to showcase platform usage and drive visitor trust

02 — Problems & Challenges

Problems & Challenges

a. API Latency & AI Context Handling

Streaming context-aware rewrites from large language models (LLMs) can cause high request latencies. If a connection drops during processing, users experience blank outputs and lost credits.

We solved this by establishing optimized prompt pipelines and word limits on our backend endpoints. The system validates text length (enforcing a strict 300-word limit on free requests and 1,000 words on Pro queries) and parses GPT payloads efficiently, keeping response times under 2 seconds.

b. Designing an Intuitive Editor UI

Content editors must let users compare drafts and rewritten variations side by side. The interface needs to support light and dark modes natively without flickering or layouts shifting during transitions.

We designed a responsive dual-panel layout styled with Tailwind CSS. We integrated a global theme toggler in the header, enabling users to switch between light and dark modes instantly. The selection is saved in local storage to prevent style flashes on subsequent visits.

c. Implementing Scalable Subscription Models

Transitioning users from free trials to paid tiers requires a clear pricing layout and secure billing checks. Free limits must be checked dynamically to prevent abuse.

We programmed pricing controls to differentiate free and paid usage. Free users are capped at 3 rewrites per week and restricted to standard tones (Professional, Humble Brag, Storytelling, Thought Leader, Casual). Paid users ($5/month) gain unlimited rewrites, advanced tones, and priority processing.

03 — Project Goals

Project Goals

a. Empowering Content Creators

We aimed to simplify content rewriting for creators. By offering one-click presets like "Humble Brag" or "Thought Leader", the platform helps creators format text for LinkedIn or Twitter without manual editing.

b. Bypassing AI Detection Limits

Our goal was to ensure rewritten outputs read naturally. We engineered custom system prompts that instruct LLMs to adjust active verbs, vary sentence lengths, and avoid predictable AI vocabulary, producing human-like text.

04 — Design Process

Design Process

a. Conversion-Optimized UI/UX

We designed the landing page to maximize user conversion. The hero section features a direct call-to-action button ("Try it Free") and a live global generation counter showcasing usage activity to establish visitor trust.

b. Prompt Engineering & Backend Integration Flow

We tested system prompts to find the right balance of creativity and structure. When a user triggers a rewrite, the backend combines their draft with the selected tone instructions, formats the request for the OpenAI API, and returns the result.

05 — Usability Testing

Usability Testing

a. Output Quality Assurance

We evaluated rewritten variations against readability metrics. We verified that outputs match the selected tone preset—checking that "Casual" adds humor and emojis, while "Professional" refines vocabulary.

b. Load Handling for Concurrent Generations

We performed load tests to verify how the backend processes concurrent generations. We implemented request throttling and rate limiting on the rewrite endpoints to protect API keys from abuse during traffic spikes.

06 — Prototyping & Handoff

Prototyping & Handoff

a. Production Deployment

We deployed the frontend to static CDN hosting to minimize latency, while hosting the backend API server on auto-scaling containers, ensuring the platform handles visitor spikes smoothly.

b. Payment Gateway Integration Setup

To streamline checkout, we set up Stripe billing. When a user clicks "Upgrade to Pro", the app routes them to Stripe Checkout, handles payments, and updates their account plan via secure webhook callbacks.

07 — Key Takeaways

Key Takeaways

a. Building High-Value AI SaaS

AI SaaS applications require simple authentication. Using Google OAuth instead of standard forms reduces sign-up friction, helping users test tools and convert to paid plans quickly.

b. Merging Advanced LLMs with Seamless Interfaces

The value of an AI wrapper lies in its usability. Offering pre-configured tone prompts in a dual-panel layout provides a better user experience than writing manual prompts in generic chatbot fields.