docs: comprehensive documentation - README, specs, architecture, API reference, UI/UX flow, dev guide

2026-04-24 15:02:40 -07:00
parent 5bde4e3aa6
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--- a/README.md
+++ b/README.md
@@ -1,36 +1,148 @@
-This is a [Next.js](https://nextjs.org) project bootstrapped with [`create-next-app`](https://nextjs.org/docs/app/api-reference/cli/create-next-app).
+# ComparAIson

-## Getting Started
+**AI-Powered Deep Research Comparison Platform**

-First, run the development server:
+Compare anything with intelligent, multi-dimensional analysis. ComparAIson uses LLM-powered research to generate comprehensive, visual comparisons — then saves them as shareable posts on your profile.
+
+## Features
+
+- **Deep Research Engine** — Multi-provider LLM pipeline (Tavily search → Perplexity/OpenAI synthesis) with automatic fallback
+- **Interactive Visualizations** — Radar charts, grouped bar charts, feature comparison tables, score cards, pros/cons breakdowns
+- **Real-Time Streaming** — Watch research progress live via Server-Sent Events
+- **User Profiles** — Save comparisons to your profile, browse a public feed
+- **Self-Hosted** — Docker Compose deployment, runs on a Raspberry Pi
+
+## Tech Stack
+
+| Layer | Technology |
+|---|---|
+| Framework | Next.js 15 (App Router, Server Components, Server Actions) |
+| Language | TypeScript |
+| Database | PostgreSQL 16 |
+| ORM | Drizzle ORM |
+| Auth | Better Auth (email + password) |
+| UI | Tailwind CSS + shadcn/ui |
+| Charts | Recharts |
+| LLM | OpenAI GPT-4o-mini + Tavily Search + Perplexity Sonar |
+| Deployment | Docker Compose + Traefik reverse proxy |
+
+## Quick Start
+
+### Prerequisites
+
+- Node.js 20+
+- PostgreSQL 16+ (or Docker)
+- At least one LLM API key
+
+### 1. Clone & Install
+
+```bash
+git clone https://gitea.tophermayor.com/TopherMayor/comparaison.git
+cd comparaison
+npm install
+```
+
+### 2. Configure Environment
+
+```bash
+cp .env.example .env.local
+# Edit .env.local with your API keys and database URL
+```
+
+Required environment variables:
+
+| Variable | Description | Required |
+|---|---|---|
+| `DATABASE_URL` | PostgreSQL connection string | Yes |
+| `BETTER_AUTH_SECRET` | Random secret for session signing | Yes |
+| `OPENAI_API_KEY` | OpenAI API key (GPT-4o-mini) | Yes* |
+| `TAVILY_API_KEY` | Tavily search API key | Recommended |
+| `PERPLEXITY_API_KEY` | Perplexity Sonar API key | Optional |
+| `NEXT_PUBLIC_APP_URL` | Public URL of the app | Yes |
+
+*At minimum, one LLM provider key is required. OpenAI works standalone; Tavily adds web search; Perplexity adds cheaper synthesis.
+
+### 3. Database Setup
+
+```bash
+# Generate migration
+npx drizzle-kit generate
+
+# Run migration
+npx drizzle-kit migrate
+```
+
+### 4. Development

 ```bash
 npm run dev
-# or
-yarn dev
-# or
-pnpm dev
-# or
-bun dev
+# App runs at http://localhost:3000
 ```

-Open [http://localhost:3000](http://localhost:3000) with your browser to see the result.
+### 5. Docker Deployment

-You can start editing the page by modifying `app/page.tsx`. The page auto-updates as you edit the file.
+```bash
+docker compose up -d
+```

-This project uses [`next/font`](https://nextjs.org/docs/app/building-your-application/optimizing/fonts) to automatically optimize and load [Geist](https://vercel.com/font), a new font family for Vercel.
+## Project Structure

-## Learn More
+```
+src/
+├── app/
+│   ├── (auth)/              # Auth route group
+│   │   ├── sign-in/         # Sign in page
+│   │   └── sign-up/         # Sign up page
+│   ├── (main)/              # Main app route group (with nav)
+│   │   ├── compare/         # Comparison input + results
+│   │   ├── explore/         # Public comparisons feed
+│   │   └── profile/         # User profile + saved comparisons
+│   ├── api/
+│   │   ├── auth/[...all]/   # Better Auth catch-all
+│   │   └── compare/         # SSE streaming research endpoint
+│   ├── layout.tsx           # Root layout
+│   └── page.tsx             # Landing page
+├── components/
+│   ├── comparison/          # Visualization components
+│   │   ├── radar-chart.tsx
+│   │   ├── bar-chart.tsx
+│   │   ├── comparison-table.tsx
+│   │   ├── score-card.tsx
+│   │   └── pros-cons-card.tsx
+│   └── ui/                  # shadcn/ui components
+├── hooks/
+│   └── use-comparison-stream.ts  # SSE streaming hook
+├── lib/
+│   ├── auth.ts              # Better Auth server config
+│   ├── auth-client.ts       # Better Auth client
+│   ├── db/
+│   │   ├── index.ts         # Drizzle client
+│   │   └── schema.ts        # Database schema
+│   ├── llm/
+│   │   ├── index.ts         # Research pipeline orchestrator
+│   │   ├── types.ts         # LLM type definitions
+│   │   └── providers/
+│   │       ├── index.ts     # Provider fallback chain
+│   │       ├── openai.ts    # OpenAI GPT-4o-mini provider
+│   │       ├── tavily.ts    # Tavily search provider
+│   │       └── perplexity.ts # Perplexity Sonar provider
+│   ├── types.ts             # Shared type definitions
+│   └── utils.ts             # Utility functions
+└── middleware.ts             # Auth middleware + route protection
+```

-To learn more about Next.js, take a look at the following resources:
+## Architecture

- [Next.js Documentation](https://nextjs.org/docs) - learn about Next.js features and API.
- [Learn Next.js](https://nextjs.org/learn) - an interactive Next.js tutorial.
+See [docs/architecture.md](docs/architecture.md) for detailed architecture documentation.

-You can check out [the Next.js GitHub repository](https://github.com/vercel/next.js) - your feedback and contributions are welcome!
+## API Reference

-## Deploy on Vercel
+See [docs/api-reference.md](docs/api-reference.md) for endpoint documentation.

-The easiest way to deploy your Next.js app is to use the [Vercel Platform](https://vercel.com/new?utm_medium=default-template&filter=next.js&utm_source=create-next-app&utm_campaign=create-next-app-readme) from the creators of Next.js.
+## UI/UX Flow

-Check out our [Next.js deployment documentation](https://nextjs.org/docs/app/building-your-application/deploying) for more details.
+See [docs/ui-ux-flow.md](docs/ui-ux-flow.md) for user journey and wireframe descriptions.
+
+## License
+
+MIT
--- a/docs/api-reference.md
+++ b/docs/api-reference.md
@@ -0,0 +1,204 @@
+# ComparAIson — API Reference
+
+## Base URL
+
+```
+Development: http://localhost:3000
+Production:  https://comparaison.tophermayor.com
+```
+
+---
+
+## Authentication
+
+All authenticated endpoints use Better Auth session cookies.
+
+### POST `/api/auth/sign-up`
+Create a new account.
+
+**Request:**
+```json
+{
+  "name": "Alex Johnson",
+  "email": "alex@example.com",
+  "password": "securepassword123"
+}
+```
+
+**Response:** `200 OK` — Sets session cookie, returns user object
+
+### POST `/api/auth/sign-in`
+Sign in to existing account.
+
+**Request:**
+```json
+{
+  "email": "alex@example.com",
+  "password": "securepassword123"
+}
+```
+
+**Response:** `200 OK` — Sets session cookie, redirects to callbackUrl
+
+### POST `/api/auth/sign-out`
+Sign out, clears session.
+
+**Response:** `200 OK` — Redirects to `/`
+
+---
+
+## Comparison Endpoints
+
+### POST `/api/compare`
+Start a new comparison research. Returns a Server-Sent Events stream.
+
+**Authentication:** Required
+
+**Request:**
+```json
+{
+  "query": "for modern web development",
+  "items": ["React", "Vue", "Svelte"],
+  "dimensions": ["Performance", "Developer Experience"]
+}
+```
+
+| Field | Type | Required | Description |
+|---|---|---|---|
+| `query` | string | No | Context/focus for the comparison |
+| `items` | string[] | Yes | Items to compare (2-10) |
+| `dimensions` | string[] | No | Optional dimension hints |
+
+**Response:** `200 OK` — `text/event-stream`
+
+SSE event format:
+```
+event: progress
+data: {"status":"researching","message":"Analyzing comparison request...","itemsCompleted":0,"totalItems":3,"currentStep":"Analyzing comparison request..."}
+
+event: progress
+data: {"status":"researching","message":"Researching React...","itemsCompleted":1,"totalItems":3,"currentStep":"Analyzing React"}
+
+event: progress
+data: {"status":"completed","message":"Research complete!","itemsCompleted":3,"totalItems":3,"currentStep":"Done"}
+
+event: done
+data: {"id":"clx123abc","slug":"react-vs-vue-vs-svelte-clx123","data":{...full comparison data...}}
+```
+
+**Error Response:** `400 Bad Request`
+```json
+{ "error": "At least 2 items are required" }
+```
+
+---
+
+## Page Routes
+
+### `GET /`
+Landing page. Public. Shows hero, example comparisons, features.
+
+### `GET /sign-in`
+Sign in form. Public. Redirects to `/compare` on success.
+
+### `GET /sign-up`
+Sign up form. Public. Redirects to `/compare` on success.
+
+### `GET /compare`
+Comparison creation page. **Protected.** Shows item input form + streaming progress.
+
+### `GET /compare/[slug]`
+Comparison results page. Public (if comparison is public). Shows tabbed visualization layout.
+
+**URL format:** `/compare/react-vs-vue-vs-svelte-clx123a`
+
+### `GET /explore`
+Public comparisons feed. Public. Grid layout with search + category filter.
+
+### `GET /profile`
+User profile page. **Protected.** Shows user info, stats, and saved comparisons.
+
+---
+
+## TypeScript Types
+
+### ComparisonRequest
+```typescript
+interface ComparisonRequest {
+  query: string;
+  items: string[];
+  dimensions?: string[];
+}
+```
+
+### ComparisonResult
+```typescript
+interface ComparisonResult {
+  items: ItemResearch[];
+  dimensions: string[];
+  summary: string;
+  recommendation: string;
+}
+```
+
+### ItemResearch
+```typescript
+interface ItemResearch {
+  name: string;
+  description: string;
+  overallScore: number;
+  dimensions: Record<string, DimensionResult>;
+  pros: string[];
+  cons: string[];
+  sources: { title: string; url: string; snippet: string }[];
+}
+```
+
+### DimensionResult
+```typescript
+interface DimensionResult {
+  score: number;       // 1-10
+  summary: string;
+  details: string;
+  pros: string[];
+  cons: string[];
+}
+```
+
+### ResearchProgress (SSE)
+```typescript
+type ResearchProgress =
+  | { stage: "parsing"; message: string }
+  | { stage: "searching"; item: string; results: number }
+  | { stage: "researching"; item: string; progress: number }
+  | { stage: "synthesizing"; message: string }
+  | { stage: "complete"; result: ComparisonResult }
+  | { stage: "error"; error: string };
+```
+
+### ComparisonData (Frontend)
+```typescript
+interface ComparisonData {
+  id: string;
+  userId: string;
+  title: string;
+  query: string;
+  slug: string;
+  status: "researching" | "completed" | "failed";
+  summary: string;
+  items: {
+    name: string;
+    description: string;
+    overallScore: number;
+    dimensions: Record<string, DimensionResult>;
+    pros: string[];
+    cons: string[];
+  }[];
+  dimensions: string[];
+  tags: string[];
+  isPublic: boolean;
+  viewCount: number;
+  createdAt: string;
+  updatedAt: string;
+}
+```
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -0,0 +1,129 @@
+# ComparAIson — Architecture
+
+## System Overview
+
+```
+┌─────────────┐     ┌──────────────┐     ┌─────────────┐
+│   Browser    │────▶│   Traefik    │────▶│   Next.js   │
+│  (React SPA) │◀────│  (Reverse    │◀────│  (Port 3000)│
+│              │     │   Proxy)     │     │             │
+└─────────────┘     └──────────────┘     └──────┬──────┘
+                                                  │
+                                    ┌─────────────┼─────────────┐
+                                    ▼             ▼             ▼
+                              ┌──────────┐ ┌──────────┐ ┌──────────┐
+                              │PostgreSQL│ │  Tavily  │ │  OpenAI  │
+                              │  (DB)    │ │ (Search) │ │  (LLM)   │
+                              └──────────┘ └──────────┘ └──────────┘
+                                                        ┌──────────┐
+                                                        │Perplexity│
+                                                        │ (LLM)    │
+                                                        └──────────┘
+```
+
+## Component Architecture
+
+### Frontend (Next.js App Router)
+
+```
+Route Groups:
+├── (auth)/          — Unauthenticated pages (sign-in, sign-up)
+├── (main)/          — Authenticated pages with shared nav layout
+│   ├── compare/     — Comparison creation + results viewing
+│   ├── explore/     — Public feed browsing
+│   └── profile/     — User profile + comparison history
+└── api/             — Server-side API routes
+    ├── auth/        — Better Auth endpoints
+    └── compare/     — SSE research streaming endpoint
+```
+
+**Key patterns:**
+- **Server Components** for data-fetching pages (profile, explore)
+- **Client Components** for interactive UI (compare input, charts, streaming)
+- **Server Actions** for mutations (save comparison, update profile)
+- **SSE streaming** for real-time research progress
+
+### Backend Services
+
+#### Research Pipeline (`src/lib/llm/`)
+Orchestrates the multi-stage research process:
+1. **Input parsing** — Validate items, extract dimensions
+2. **Provider detection** — Check available API keys, select best provider chain
+3. **Web search** — Tavily API searches per item
+4. **LLM synthesis** — Structured JSON generation via Perplexity or OpenAI
+5. **Validation** — Runtime type checking of LLM output
+6. **Persistence** — Store results in PostgreSQL via Drizzle ORM
+
+#### Auth System (`src/lib/auth.ts`)
+- Better Auth with Drizzle adapter
+- Email + password authentication
+- 7-day session expiry
+- Middleware-based route protection
+
+#### Database (`src/lib/db/`)
+- Drizzle ORM with PostgreSQL
+- 5 tables: users, sessions, comparisons, comparison_items, comparison_dimensions
+- JSONB columns for flexible research data storage
+- Indexed on userId, slug, status for query performance
+
+## Data Flow
+
+### Comparison Creation Flow
+
+```
+1. User enters items + query on /compare
+2. Client calls POST /api/compare with { items, query, dimensions }
+3. Server creates comparison record (status: "researching")
+4. Server opens SSE stream to client
+5. Research pipeline runs:
+   a. Parsing → emits SSE "parsing" event
+   b. For each item:
+      - Tavily search → emits SSE "searching" event
+      - Process results → emits SSE "researching" event with progress %
+   c. Synthesize all data → emits SSE "synthesizing" event
+   d. Validate + structure → emits SSE "complete" event with full data
+6. Server persists results to comparisons + comparison_items tables
+7. Client renders visualization components with result data
+8. User redirected to /compare/[slug] with full results
+```
+
+### Comparison Viewing Flow
+
+```
+1. User navigates to /compare/[slug]
+2. Server component fetches comparison from DB by slug
+3. If status === "researching": show streaming progress UI
+4. If status === "completed": render full results with all viz components
+5. If status === "failed": show error with retry option
+6. Increment viewCount on each visit
+```
+
+## Deployment Architecture
+
+### Docker Compose
+
+```yaml
+services:
+  app:        # Next.js standalone (~150-300MB RAM)
+  db:         # PostgreSQL 16 Alpine (~200-400MB RAM)
+```
+
+Total estimated RAM: **400-800MB** — fits comfortably on an 8GB Raspberry Pi.
+
+### Traefik Integration
+
+The app is exposed via Traefik reverse proxy with:
+- HTTPS termination
+- Domain routing (e.g., `comparaison.tophermayor.com`)
+- Automatic SSL certificate management
+
+## Error Handling
+
+| Layer | Strategy |
+|---|---|
+| LLM API failures | 3x retry with exponential backoff |
+| Provider unavailable | Automatic fallback to next provider in chain |
+| Invalid LLM output | Runtime validation + retry with new prompt |
+| Database errors | Transaction rollback, error logged, user sees "failed" status |
+| SSE connection lost | Client auto-reconnects, polls comparison status from DB |
+| Auth failures | Redirect to sign-in with callback URL |
--- a/docs/development.md
+++ b/docs/development.md
@@ -0,0 +1,86 @@
+# ComparAIson — Development Guide
+
+## Getting Started
+
+```bash
+# Clone
+git clone https://gitea.tophermayor.com/TopherMayor/comparaison.git
+cd comparaison
+
+# Install
+npm install
+
+# Environment
+cp .env.example .env.local
+# Edit .env.local with your keys
+
+# Database
+docker compose up db -d  # Start just PostgreSQL
+npx drizzle-kit generate  # Generate migrations
+npx drizzle-kit migrate   # Apply migrations
+
+# Dev server
+npm run dev
+```
+
+## Commands
+
+| Command | Description |
+|---|---|
+| `npm run dev` | Start dev server (port 3000) |
+| `npm run build` | Production build (standalone output) |
+| `npm run start` | Start production server |
+| `npm run lint` | ESLint check |
+| `npx tsc --noEmit` | Type check without building |
+| `npx drizzle-kit generate` | Generate DB migrations from schema |
+| `npx drizzle-kit migrate` | Apply migrations to database |
+| `npx drizzle-kit studio` | Open Drizzle Studio (DB browser) |
+
+## Branch Strategy
+
+| Branch | Purpose |
+|---|---|
+| `main` | Stable, deployable code |
+| `feat/backend` | DB schema, auth, Docker, config changes |
+| `feat/llm-engine` | LLM provider changes, research pipeline |
+| `feat/frontend` | UI components, pages, layouts |
+
+Worktrees are used for parallel development:
+```bash
+git worktree add ../comparaison-backend -b feat/backend main
+```
+
+## Database Schema Changes
+
+1. Edit `src/lib/db/schema.ts`
+2. Run `npx drizzle-kit generate` to create migration SQL
+3. Run `npx drizzle-kit migrate` to apply
+4. Commit both schema.ts and the generated SQL in `drizzle/`
+
+## Adding a New LLM Provider
+
+1. Create `src/lib/llm/providers/your-provider.ts`
+2. Implement the provider function matching the `Provider` interface:
+   ```typescript
+   export async function synthesize(
+     request: ComparisonRequest,
+     searchResults: Record<string, SearchResult[]>
+   ): Promise<ComparisonResult>
+   ```
+3. Register in `src/lib/llm/providers/index.ts` — add to the fallback chain
+4. Add API key to `.env.example` and document in README
+
+## Adding a New Visualization
+
+1. Create `src/components/comparison/your-chart.tsx`
+2. Accept `ComparisonData` as props (or relevant subset)
+3. Use Recharts for chart components
+4. Import and add to the tab layout in `results-client.tsx`
+
+## Key Conventions
+
+- **Server Components** by default, `"use client"` only when needed (hooks, interactivity)
+- **Drizzle ORM** for all database queries — no raw SQL
+- **shadcn/ui** for UI components — no external component libraries
+- **Tailwind** for styling — no CSS modules or styled-components
+- **TypeScript strict mode** — no `any` types
--- a/docs/specs.md
+++ b/docs/specs.md
@@ -0,0 +1,163 @@
+# ComparAIson — Product Specification
+
+## 1. Product Overview
+
+**ComparAIson** is a self-hosted web application that enables users to compare two or more items using AI-powered deep research. The system performs multi-source research, generates structured comparison data, and presents results through interactive visualizations. Completed comparisons are saved as posts on user profiles, creating a browsable library of research.
+
+## 2. Problem Statement
+
+Comparing products, technologies, or services requires gathering data from multiple sources, synthesizing findings, and presenting them clearly. This is time-consuming and often produces inconsistent results. ComparAIson automates this process with LLM-powered research that produces structured, visual, and comparable outputs.
+
+## 3. Target Users
+
+- **Developers** comparing frameworks, tools, cloud services
+- **Consumers** comparing products before purchase
+- **Researchers** comparing methodologies, papers, or approaches
+- **Teams** evaluating options for technical decisions
+
+## 4. Core Features
+
+### 4.1 AI Research Engine
+- Multi-item comparison (2-10 items)
+- Multi-dimensional scoring (5-8 dimensions per comparison)
+- Web search integration via Tavily API
+- LLM synthesis via OpenAI GPT-4o-mini or Perplexity Sonar
+- Automatic provider fallback chain
+- Structured JSON output with validation
+- Server-Sent Events for real-time progress
+
+### 4.2 Interactive Visualizations
+- **Radar/Spider Chart** — Multi-dimensional overlay showing all items
+- **Grouped Bar Chart** — Side-by-side metric comparison
+- **Comparison Table** — Feature matrix with color-coded cells
+- **Score Cards** — Animated progress bars with overall + per-dimension scores
+- **Pros/Cons Cards** — Expandable per-item breakdown
+
+### 4.3 User System
+- Email + password authentication (Better Auth)
+- Session management (7-day expiry)
+- Protected routes for compare/profile actions
+- Public profile pages with comparison history
+
+### 4.4 Social/Feed Features
+- Public comparisons feed (Explore page)
+- Per-comparison view count tracking
+- Tag-based categorization and filtering
+- Search across public comparisons
+- Shareable URLs for each comparison
+
+## 5. Technical Constraints
+
+| Constraint | Value |
+|---|---|
+| Deployment target | Raspberry Pi ARM64, 8GB RAM |
+| Concurrent users | Low (homelab, <20) |
+| Total RAM budget | ~500MB-1GB (app + DB + reverse proxy) |
+| Cost target | Minimal (free tier APIs where possible) |
+| Network | Behind Traefik reverse proxy with HTTPS |
+
+## 6. Data Model
+
+### 6.1 Users (Better Auth managed)
+```
+users: id, name, email, emailVerified, image, createdAt, updatedAt
+sessions: id, userId (FK), token, expiresAt, createdAt, updatedAt
+```
+
+### 6.2 Comparisons
+```
+comparisons: id, userId (FK), title, query, slug, status (researching|completed|failed),
+             summary, overallData (JSONB), tags[], isPublic, viewCount, createdAt, updatedAt
+```
+
+### 6.3 Comparison Items
+```
+comparison_items: id, comparisonId (FK), name, description, imageUrl,
+                  researchData (JSONB), scores (JSONB), pros[], cons[], order
+```
+
+### 6.4 Comparison Dimensions
+```
+comparison_dimensions: id, comparisonId (FK), name, description, weight, order
+```
+
+### 6.5 JSONB Schemas
+
+**overallData (on comparisons):**
+```json
+{
+  "title": "React vs Vue vs Svelte",
+  "query": "for modern web development",
+  "status": "completed",
+  "summary": "...",
+  "items": [
+    {
+      "name": "React",
+      "description": "...",
+      "overallScore": 8.5,
+      "dimensions": {
+        "Performance": { "score": 8, "summary": "...", "details": "...", "pros": [], "cons": [] }
+      },
+      "pros": ["..."],
+      "cons": ["..."]
+    }
+  ],
+  "dimensions": ["Performance", "Developer Experience", "Ecosystem", ...]
+}
+```
+
+**researchData (on comparison_items):**
+Full `ItemResearch` object including dimensions, sources, and scores.
+
+## 7. LLM Research Pipeline
+
+### 7.1 Flow
+```
+User submits query
+  → Parse request (validate items ≥ 2)
+  → Detect available providers (Tavily? Perplexity? OpenAI?)
+  → If Tavily available: search each item individually
+  → Synthesize via best available provider:
+      Priority 1: Tavily search + Perplexity synthesis
+      Priority 2: Tavily search + OpenAI synthesis
+      Priority 3: OpenAI only (no web search)
+  → Validate structured JSON output
+  → Persist to database
+  → Stream results to client
+```
+
+### 7.2 Provider Details
+
+| Provider | Role | Model | Cost |
+|---|---|---|---|
+| Tavily | Web search | Search API | ~$0.005/search |
+| Perplexity | Synthesis | Sonar | ~$0.002/query |
+| OpenAI | Synthesis | GPT-4o-mini | ~$0.15/1M tokens |
+
+### 7.3 Progress Stages (SSE)
+1. `parsing` — Validating query and extracting items
+2. `searching` — Running web search for each item (Tavily only)
+3. `researching` — Processing research per item
+4. `synthesizing` — LLM generating structured comparison
+5. `complete` — Final result with all data
+6. `error` — Failure with error message
+
+## 8. Security Considerations
+
+- Auth middleware protects `/compare` and `/profile` routes
+- Session tokens stored in HTTP-only cookies
+- API keys never exposed to client (server-only LLM calls)
+- Input validation on all API endpoints (min 2 items, max 10)
+- SQL injection prevented via Drizzle ORM parameterized queries
+- CSRF protection via Better Auth
+- Rate limiting placeholder in compare API route
+
+## 9. Future Considerations
+
+- [ ] OAuth providers (Google, GitHub)
+- [ ] Comparison comments/likes
+- [ ] Export to PDF/image
+- [ ] Embeddable comparison widgets
+- [ ] Comparison templates
+- [ ] Batch comparison queue for heavy loads
+- [ ] Local Ollama fallback for offline operation
--- a/docs/ui-ux-flow.md
+++ b/docs/ui-ux-flow.md
@@ -0,0 +1,343 @@
+# ComparAIson — UI/UX Flow
+
+## User Journeys
+
+### Journey 1: New User Discovers → Signs Up → First Comparison
+
+```
+Landing Page (/)
+    │
+    ▼ "Start Comparing" CTA or /compare URL
+Sign In Page (/sign-in)
+    │ ─── "Don't have an account? Sign up"
+    ▼
+Sign Up Page (/sign-up)
+    │ User enters: name, email, password
+    │ On success → redirect to /compare
+    ▼
+Compare Page (/compare)
+    │ User enters items (2-10) + query
+    │ Clicks "Start Research"
+    ▼
+Streaming Progress
+    │ Progress bar + current step label
+    │ Steps: "Analyzing..." → "Searching React..." → "Synthesizing..."
+    ▼
+Results Page (/compare/[slug])
+    │ Tab layout: Overview | Charts | Table | Details
+    │ User explores visualizations
+    │ Comparison auto-saved to profile
+    ▼
+Profile Page (/profile)
+    │ Sees their first comparison in the grid
+    └── Can click to view again
+```
+
+### Journey 2: Returning User Quick Compare
+
+```
+Home (/) → already logged in
+    │
+    ▼ Click "Compare" in nav
+Compare Page (/compare)
+    │ Enter items + query → "Start Research"
+    ▼
+Results Page (/compare/[slug])
+    │ Review results, share URL
+    └── Return to profile or start new compare
+```
+
+### Journey 3: Anonymous User Browses Public Comparisons
+
+```
+Landing Page (/)
+    │
+    ▼ "Explore" in nav or example comparison card
+Explore Page (/explore)
+    │ Grid of public comparisons
+    │ Filter by category tags
+    │ Search by keyword
+    ▼ Click a comparison card
+Results Page (/compare/[slug])
+    │ View full results (read-only)
+    │ "Start Your Own Comparison" CTA if not logged in
+    └── Sign up flow from Journey 1
+```
+
+---
+
+## Page Descriptions
+
+### 1. Landing Page (`/`)
+**Purpose:** First impression, explain the product, drive sign-ups
+
+**Layout:**
+```
+┌─────────────────────────────────────────────┐
+│  Header: Logo "ComparAIson" | [Sign In]     │
+├─────────────────────────────────────────────┤
+│                                             │
+│     ✨ AI-Powered Research                  │
+│                                             │
+│  Compare Anything with                      │
+│  AI-Powered Deep Research                   │
+│                                             │
+│  [🚀 Start Comparing]  [Explore Examples]   │
+│                                             │
+├─────────────────────────────────────────────┤
+│  Example Comparisons (2x2 grid)             │
+│  ┌──────────────┐  ┌──────────────┐         │
+│  │ React vs Vue │  │ GPT-4 vs     │         │
+│  │ vs Svelte    │  │ Claude vs    │         │
+│  │ ⭐ 8.5       │  │ Gemini ⭐ 8.8│         │
+│  └──────────────┘  └──────────────┘         │
+│  ┌──────────────┐  ┌──────────────┐         │
+│  │ Notion vs    │  │ AWS vs GCP   │         │
+│  │ Obsidian     │  │ vs Azure     │         │
+│  └──────────────┘  └──────────────┘         │
+├─────────────────────────────────────────────┤
+│  Features (3 columns)                       │
+│  📊 Rich Viz  🔍 Deep Research  🔗 Share   │
+├─────────────────────────────────────────────┤
+│  Footer                                     │
+└─────────────────────────────────────────────┘
+```
+
+### 2. Sign In Page (`/sign-in`)
+**Purpose:** Authenticate existing users
+
+**Layout:**
+```
+Centered card, max-w-md:
+┌─────────────────────────────┐
+│     Sign In                  │
+│     Welcome back             │
+│                              │
+│  Email    [______________]   │
+│  Password [______________]   │
+│                              │
+│  [    Sign In    ]           │
+│                              │
+│  Don't have an account?      │
+│  [Sign Up]                   │
+└─────────────────────────────┘
+```
+
+- Error state: Red text below form on invalid credentials
+- Loading state: Spinner on button, disabled inputs
+- Success: Redirect to callbackUrl or /compare
+
+### 3. Sign Up Page (`/sign-up`)
+**Purpose:** Register new users
+
+**Layout:** Same as sign in but with Name field added
+```
+Name     [______________]
+Email    [______________]
+Password [______________]
+[    Create Account    ]
+Already have an account? [Sign In]
+```
+
+### 4. Compare Page (`/compare`)
+**Purpose:** Main comparison creation interface
+
+**Layout:**
+```
+Centered card, max-w-2xl:
+┌─────────────────────────────────────────┐
+│  ✨ Start a Comparison                  │
+│  Enter items to compare and let AI      │
+│  do deep research for you.              │
+│                                          │
+│  What would you like to compare?         │
+│  [________________________________]      │
+│  (textarea for natural language query)   │
+│                                          │
+│  Items to compare (min 2, max 10)        │
+│  [React ×] [Vue ×] [Svelte ×] [+ Add]  │
+│  [________________________] [Add]        │
+│                                          │
+│  Comparison dimensions (optional)        │
+│  [________________________________]      │
+│  (comma-separated hints)                 │
+│                                          │
+│  [🚀 Start Research]                     │
+│                                          │
+│  ┌─ Progress (shown during research) ──┐ │
+│  │ [████████████░░░░░░░] 60%           │ │
+│  │ 🔍 Researching Svelte...            │ │
+│  └─────────────────────────────────────┘ │
+└─────────────────────────────────────────┘
+```
+
+**Interactions:**
+- Tag-style item input: type + Enter to add, X to remove
+- Minimum 2 items required to start
+- Progress bar appears after "Start Research" clicked
+- Cancel button during research
+- Auto-redirect to results on completion
+
+### 5. Results Page (`/compare/[slug]`)
+**Purpose:** Display completed comparison with visualizations
+
+**Layout:**
+```
+┌─────────────────────────────────────────────────┐
+│ ← Back    React vs Vue vs Svelte    [Share]     │
+│ Overall: React ⭐ 8.5 | Vue ⭐ 7.8 | Svelte ⭐ 8.2│
+├─────────────────────────────────────────────────┤
+│ [Overview] [Charts] [Table] [Details]           │
+├─────────────────────────────────────────────────┤
+│                                                  │
+│  ┌── Overview Tab ─────────────────────────────┐ │
+│  │                                              │ │
+│  │  Summary text from AI                        │ │
+│  │  "React excels in ecosystem size..."         │ │
+│  │                                              │ │
+│  │  ┌─ Score Cards ────────────────────────┐   │ │
+│  │  │ React: ⭐ 8.5                        │   │ │
+│  │  │ [█████████░] Performance: 8/10       │   │ │
+│  │  │ [████████░░] DX: 9/10               │   │ │
+│  │  │ ...                                  │   │ │
+│  │  └──────────────────────────────────────┘   │ │
+│  │                                              │ │
+│  │  🏆 Recommendation: "For most projects..."  │ │
+│  └──────────────────────────────────────────────┘ │
+│                                                  │
+│  ┌── Charts Tab ──────────────────────────────┐  │
+│  │                                              │  │
+│  │  Radar Chart          Bar Chart              │  │
+│  │  ┌─────────────┐     ┌──────────────┐       │  │
+│  │  │  ╱  React ╲  │     │ ▓ ▓ ▓        │       │  │
+│  │  │ │  Vue   │  │     │ ▓ ▓ ▓        │       │  │
+│  │  │  ╲Svelte╱   │     │ ▓ ▓ ▓        │       │  │
+│  │  └─────────────┘     └──────────────┘       │  │
+│  │                                              │  │
+│  └──────────────────────────────────────────────┘ │
+│                                                  │
+│  ┌── Table Tab ───────────────────────────────┐  │
+│  │            │ React │ Vue  │ Svelte │        │  │
+│  │ Performance│  8    │  7   │   9    │        │  │
+│  │ DX         │  9    │  8   │   8    │        │  │
+│  │ Ecosystem  │  10   │  7   │   6    │        │  │
+│  │ Price      │  9    │  9   │   10   │        │  │
+│  └──────────────────────────────────────────────┘  │
+│                                                    │
+│  ┌── Details Tab ─────────────────────────────┐   │
+│  │ Per-item expandable deep dives              │   │
+│  │ ▶ React - Performance (8/10)                │   │
+│  │   Pros: Virtual DOM, concurrent mode...     │   │
+│  │   Cons: Bundle size can grow...             │   │
+│  │ ▶ Vue - Performance (7/10)                  │   │
+│  │ ...                                          │   │
+│  └──────────────────────────────────────────────┘   │
+└─────────────────────────────────────────────────────┘
+```
+
+**Interactions:**
+- Tab switching between Overview/Charts/Table/Details
+- Hover tooltips on all charts
+- Click legend items to toggle visibility on radar/bar charts
+- Expandable rows in table for detailed breakdowns
+- Share button copies URL to clipboard
+- Trophy icon highlights the winner
+
+### 6. Profile Page (`/profile`)
+**Purpose:** User's personal comparison library
+
+**Layout:**
+```
+┌─────────────────────────────────────────────┐
+│  [Avatar]  Alex Johnson                     │
+│            alex@example.com                  │
+│                                             │
+│  ┌─ Stats ─────────┐  ┌─ Stats ──────────┐ │
+│  │ 12               │  │ 8.2K              │ │
+│  │ Total Comparisons│  │ Total Views       │ │
+│  └──────────────────┘  └───────────────────┘ │
+│                                             │
+│  My Comparisons                             │
+│  ┌──────────────┐  ┌──────────────┐         │
+│  │ React vs Vue │  │ GPT-4 vs     │         │
+│  │ vs Svelte    │  │ Claude       │         │
+│  │ ⭐ 8.5 | 👁 1.2K│  │ ⭐ 8.8 | 👁 3.9K│   │
+│  │ Jan 15, 2024 │  │ Jan 10, 2024 │        │
+│  └──────────────┘  └──────────────┘         │
+│                                             │
+│  [+ New Comparison]                         │
+└─────────────────────────────────────────────┘
+```
+
+### 7. Explore Page (`/explore`)
+**Purpose:** Browse public comparisons from all users
+
+**Layout:**
+```
+┌─────────────────────────────────────────────────┐
+│  Explore Comparisons                             │
+│  [🔍 Search comparisons...]                     │
+│                                                  │
+│  [All] [Tech] [Products] [AI] [Cloud] [Prod.]   │
+│                                                  │
+│  ┌─────────┐ ┌─────────┐ ┌─────────┐           │
+│  │React vs │ │GPT-4 vs │ │iPhone vs│           │
+│  │Vue vs   │ │Claude vs │ │Samsung  │           │
+│  │Svelte   │ │Gemini   │ │S24 Ultra│           │
+│  │⭐8.5 👁1.2K│ │⭐8.8 👁3.9K│ │⭐8.2 👁3.4K│    │
+│  │by Alex  │ │by Sarah │ │by James │           │
+│  └─────────┘ └─────────┘ └─────────┘           │
+│  ┌─────────┐ ┌─────────┐ ┌─────────┐           │
+│  │AWS vs   │ │Python vs│ │Notion vs│           │
+│  │GCP vs   │ │Rust vs  │ │Obsidian │           │
+│  │Azure    │ │Go       │ │vs Roam  │           │
+│  │⭐9.0 👁2.2K│ │⭐8.4 👁1.9K│ │⭐7.5 👁892 │    │
+│  │by Emma  │ │by Anna  │ │by Mike  │           │
+│  └─────────┘ └─────────┘ └─────────┘           │
+│                                                  │
+│  [Load More]                                     │
+└─────────────────────────────────────────────────┘
+```
+
+---
+
+## Responsive Design
+
+### Desktop (≥768px)
+- Sidebar navigation on the left
+- Full-width comparison tables
+- Side-by-side charts on Charts tab
+- 3-column grid on Explore page
+
+### Mobile (<768px)
+- Bottom navigation bar (fixed)
+- Stacked charts (full width each)
+- Single column cards on Explore
+- Collapsible navigation menu
+
+---
+
+## Loading & Error States
+
+### Research Progress
+```
+┌─ Research in Progress ──────────────┐
+│ [████████████░░░░░░░░░] 60%         │
+│ 🔍 Researching Svelte...            │
+│                                      │
+│ Items: React ✓  Vue ✓  Svelte ⟳    │
+│                                      │
+│                [Cancel]              │
+└──────────────────────────────────────┘
+```
+
+### Skeleton Loaders
+- Used on results page while data loads
+- Shimmer effect on card placeholders
+- Chart skeleton rectangles
+
+### Error States
+- **API error:** Red banner with error message + "Try Again" button
+- **Auth required:** Redirect to sign-in with callback
+- **Not found:** 404 page with "Browse comparisons" link
+- **Network error:** Toast notification + retry prompt