Argus Website

Marketing website for Argus GST Billing — a Flutter-based GST invoicing and billing app for Indian businesses.

Tech Stack

• Framework: Next.js 15 (App Router, static export)
• Styling: Tailwind CSS
• Hosting: Firebase Hosting
• Functions: Firebase Cloud Functions (Node 20)
• Auth: Firebase Authentication
• Database: Firestore
• Payments: Razorpay (web subscriptions)

Getting Started

npm install
npm run dev

For local development with Cloud Functions emulator:

firebase emulators:start   # in a separate terminal
npm run dev

Environment Variables

Copy .env.example to .env.local and fill in:

• NEXT_PUBLIC_FIREBASE_API_KEY — Firebase API key
• NEXT_PUBLIC_FIREBASE_AUTH_DOMAIN — Firebase auth domain
• NEXT_PUBLIC_FIREBASE_PROJECT_ID — Firebase project ID
• NEXT_PUBLIC_FIREBASE_APP_ID — Firebase app ID
• RAZORPAY_KEY_ID — Razorpay key ID (set as Cloud Functions secret)
• RAZORPAY_KEY_SECRET — Razorpay key secret (set as Cloud Functions secret, never expose to client)

Cloud Functions secrets are set via:

firebase functions:secrets:set RAZORPAY_KEY_ID
firebase functions:secrets:set RAZORPAY_KEY_SECRET

Firebase Admin SDK auto-initializes in Cloud Functions — no service account key needed.

Project Structure

app/              - Next.js App Router pages (marketing + /app web app)
components/       - React components (marketing + web app)
lib/              - Firebase config, auth provider, Razorpay utils, types, storage, GST utils
functions/        - Firebase Cloud Functions (API endpoints, rate limiting)
  _shared/        - Shared modules (firebase-admin, plans, rate-limit)
  index.js        - All Cloud Function endpoints
public/           - Static assets (logo, store badges)
_legacy/          - Original static HTML site (kept for reference)

Deployment

npm run build
firebase deploy

This deploys:

• Static site to Firebase Hosting (serves out/ directory)
• Cloud Functions to Firebase Functions
• API routes are wired via firebase.json rewrites

Custom Domain

To set up argusinvoicing.com as the main domain:

1. Go to Firebase Console > Hosting > Add custom domain
2. Enter argusinvoicing.com
3. Add the provided DNS A/CNAME records to your domain registrar
4. Wait for SSL provisioning (usually 15-30 minutes)
5. Add www.argusinvoicing.com as a redirect to the apex domain

Rate Limiting

All API endpoints have rate limiting stored in Firestore (rate_limits collection):

Endpoint	Limit	Window
/api/auth/sync	1 call	1 hour
/api/user/profile (GET)	10 calls	1 minute
/api/user/profile (PUT)	5 calls	1 minute
/api/payment/create-order	5 calls	1 minute
/api/payment/verify	5 calls	1 minute

This prevents runaway Firebase billing from excessive syncs or abuse.

Related

• Argus App Repo — Flutter mobile app