Code Review Tool

An AI-powered code review tool that automatically reviews GitHub pull requests using Claude (Anthropic), posts inline comments, and sends Slack/email notifications.

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UI

Figure 1 — Reviews dashboard

Figure 2 — Analytics dashboard

Figure 3 — Slack notification

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Architecture

code-review-tool/
├── api/          Express + Prisma + BullMQ backend
├── web/          Next.js 14 frontend
├── packages/
│   └── types/    Shared TypeScript interfaces
└── docker-compose.yml  Postgres + Redis

Request flow:

1. GitHub sends a webhook on PR open/sync
2. API verifies HMAC signature, enqueues a BullMQ job
3. Worker fetches the diff, chunks it, calls Claude for review
4. Review is saved to Postgres, posted to GitHub as inline comments
5. Slack and/or email notifications are sent (fire-and-forget)

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Prerequisites

• Node.js 20+
• Docker (for Postgres and Redis)
• A GitHub OAuth App
• An Anthropic API key
• (Optional) Resend API key for email notifications
• (Optional) A public URL for GitHub webhooks (e.g. ngrok)

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Local Setup

1. Install dependencies

npm install

2. Start infrastructure

docker-compose up -d

This starts:

• Postgres on localhost:5433 (main DB)
• Postgres shadow on localhost:5434 (Prisma migrations)
• Redis on localhost:6379

3. Configure environment variables

Copy .env.example to api/.env and fill in the values:

cp .env.example api/.env

Required values:

Variable	Description
DATABASE_URL	postgres://postgres:postgres@localhost:5433/code_review_tool?sslmode=disable
SHADOW_DATABASE_URL	postgres://postgres:postgres@localhost:5434/code_review_tool_shadow?sslmode=disable
REDIS_URL	redis://localhost:6379
JWT_SECRET	Any random secret string
GITHUB_CLIENT_ID	From your GitHub OAuth App
GITHUB_CLIENT_SECRET	From your GitHub OAuth App
GITHUB_CALLBACK_URL	http://localhost:4000/auth/github/callback
WEBHOOK_SECRET	Any random string (must match your GitHub webhook config)
WEBHOOK_URL	Public URL where GitHub can reach your API (e.g. ngrok URL)
ANTHROPIC_API_KEY	From console.anthropic.com
WEB_URL	http://localhost:3000

Optional:

Variable	Description
RESEND_API_KEY	From resend.com for email notifications

Also create web/.env.local:

echo "NEXT_PUBLIC_API_URL=http://localhost:4000" > web/.env.local
echo "API_URL=http://localhost:4000" >> web/.env.local

4. Run database migrations

cd api
npx prisma migrate dev

5. Start everything

Open three terminals:

Terminal 1 — API server:

npm run dev:api
# or: cd api && npm run dev

Terminal 2 — Background worker:

cd api
npx ts-node-dev --respawn --transpile-only src/queue/worker.ts

Terminal 3 — Web frontend:

npm run dev:web
# or: cd web && npm run dev

Then open http://localhost:3000.

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Exposing webhooks locally (ngrok)

GitHub needs a public URL to deliver webhook events. In a fourth terminal:

ngrok http 4000

Copy the https:// URL ngrok gives you and set it in api/.env:

WEBHOOK_URL=https://abc123.ngrok.io

Restart the API server after changing this value.

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Setting up GitHub OAuth

1. Go to GitHub → Settings → Developer settings → OAuth Apps
2. Click New OAuth App
3. Set Homepage URL to http://localhost:3000
4. Set Authorization callback URL to http://localhost:4000/auth/github/callback
5. Copy the Client ID and Client Secret into api/.env

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Running Tests

cd api
npm test

Tests use Vitest with mocked Prisma, BullMQ, and the Gemini SDK — no real DB or Redis connection needed.

To run in watch mode during development:

cd api
npx vitest

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Pages

Route	Description
/	Landing page
/login	GitHub OAuth login
/dashboard	Overview
/dashboard/repos	Enable/disable repos, configure notifications
/dashboard/reviews	Review history with filters and detail panel
/dashboard/analytics	Charts: score over time, security issues, volume, leaderboard

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API Endpoints

Method	Path	Description
GET	/auth/github	Start GitHub OAuth flow
GET	/auth/me	Get current user
POST	/auth/logout	Clear session
POST	/github/webhook	GitHub webhook receiver
GET	/repos/available	List GitHub repos with enabled status
POST	/repos/register	Enable a repo (creates webhook)
DELETE	/repos/disable	Disable a repo (removes webhook)
PATCH	/repos/settings	Update notification email/Slack URL
GET	/reviews	Paginated review history
GET	/reviews/export	Download reviews as CSV
GET	/analytics	Aggregate stats and chart data
GET	/admin/queues	BullMQ dashboard

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Tech Stack

• API: Express, Prisma, BullMQ, Google Gemini SDK
• Web: Next.js 14, Tailwind CSS, Recharts
• DB: PostgreSQL (via Prisma)
• Queue: Redis + BullMQ
• Auth: GitHub OAuth + JWT (httpOnly cookie)
• Notifications: Resend (email), Slack Incoming Webhooks
• CI: GitHub Actions