AI Code Reviewer

An intelligent automated code review system that integrates with GitHub to analyze pull request changes using AI and post inline review comments.

Architecture

PR opened/synchronized
       │
       ▼
 GitHub Webhook
       │
       ▼
 processPR() ──► fetch PR files via GitHub App installation token
       │
       ▼
 parseDiff() ──► extract added lines per file
       │
       ▼
 reviewCode() ──► Groq (Llama 3.3 70B) code review
       │
       ▼
 postGitHubReview() ──► inline comments on PR
       │
       ▼
 store Review + Issues in PostgreSQL (Prisma)

Features

• GitHub App integration — authenticates via JWT and installation tokens; no PAT required
• Webhook-driven — reviews PRs automatically on opened and synchronize events
• AI-powered reviews — uses Llama 3.3 70B via Groq to identify bugs, warnings, and suggestions
• Inline PR comments — posts specific, line-level review comments on GitHub
• Review dashboard — tracks total reviews, issues found, and bugs caught per user
• Persistent storage — all reviews and issues are stored in PostgreSQL via Prisma

Tech Stack

• Framework: Next.js 16 (App Router)
• Language: React 19
• AI: Groq SDK — llama-3.3-70b-versatile
• Database ORM: Prisma
• Database: PostgreSQL
• Auth: NextAuth.js (GitHub OAuth + GitHub App tokens)
• UI: Tailwind CSS + shadcn/ui (Radix UI)
• Client: jsonwebtoken (GitHub App JWT signing)

Prerequisites

• Node.js >= 18
• PostgreSQL
• A GitHub App with:
  • Permissions: Pull requests (Read & Write), Commit statuses (Read), Contents (Read), Metadata (Read)
  • Events: Pull request, Installation
• A Groq API key
• A GitHub Personal Access Token (PAT) with repo scope (used as fallback for posting reviews)

Setup

git clone <repo-url>
cd ai-code-reviewer
npm install

Database

npx prisma migrate dev --name init

Environment Variables

Create a .env file at the project root:

DATABASE_URL=postgresql://user:password@localhost:5432/ai_code_reviewer

GITHUB_CLIENT_ID=your_github_oauth_client_id
GITHUB_CLIENT_SECRET=your_github_oauth_client_secret

GITHUB_APP_ID=your_github_app_id
GITHUB_APP_PRIVATE_KEY_BASE64=base64_encoded_app_private_key
GITHUB_PAT=your_github_personal_access_token

GROQ_API_KEY=your_groq_api_key

NEXTAUTH_URL=http://localhost:3000
NEXTAUTH_SECRET=your_nextauth_secret

AUTH_SECRET=your_auth_secret
GITHUB_WEBHOOK_SECRET=your_webhook_secret
AUTH_GROQ_API_KEY=your_app_owner_groq_key

Run

npm run dev

Visit http://localhost:3000.

Project Structure

app/
  api/
    auth/[...nextauth]/route.js    — NextAuth GitHub OAuth handler
    webhook/github/route.js        — GitHub webhook receiver (PR events)
  dashboard/page.js                — User review dashboard
  page.js                          — Landing page

lib/
  db.js                            — Prisma client singleton
  github.js                        — GitHub App JWT, installation tokens, PR file fetch, review posting
  parseDiff.js                     — Unified diff parser, extracts added lines
  aiReview.js                      — Groq LLM code review logic
  postReview.js                    — Post review comments to GitHub via PAT

prisma/
  schema.prisma                    — User, Installation, Review, Issue models

Deployment

• Deploy to any Node.js host (Vercel, Railway, Render, Fly.io)
• Ensure NEXTAUTH_URL points to your production domain
• Configure GitHub App webhooks to point to https://your-app.com/api/webhook/github
• Expose via tunnel (e.g., ngrok) during local development:

npx ngrok http 3000

License

MIT