Crypto Guardian

A crypto wallet safety checker. Paste any blockchain address and instantly see if it's safe to interact with. Analyzes transaction patterns, checks against known scam databases, and assigns a risk score.

Built with React, TypeScript, and Vercel Serverless Functions. Supports Ethereum, Bitcoin, and EVM chains.

Quick Start

pnpm install
pnpm dev

Frontend + API available at http://localhost:5173

Prerequisites

• Node.js 24+ (.nvmrc)
• pnpm 10.0.0+

Environment

Set these in Vercel's dashboard (Settings → Environment Variables) or in frontend/.env for local development:

ETHERSCAN_API_KEY=your_key_here

Get a free Etherscan API key at https://etherscan.io/apis

Tech Stack

• Frontend: Vite + React + TypeScript + Tailwind CSS + Radix UI
• API: Vercel Serverless Functions (Node.js)
• APIs: Etherscan V2 (free key), BlockCypher (free)
• Prices: Blockchain.info (BTC), Coinbase (ETH, BNB, MATIC, ARB)
• Blacklist: ScamSniffer (community-maintained scam address database)

Architecture

frontend/
  api/                    # Vercel serverless functions
    check-address.ts      # POST /api/check-address
    supported-chains.ts   # GET /api/supported-chains
  lib/                    # Shared business logic (used by serverless functions)
    services/             # blockchainApis, riskAnalyzer, blacklist, priceAPI
    types/                # TypeScript types
    utils/                # Address validation
    config.ts             # Environment config
  src/                    # React frontend
    services/api.ts       # Fetch client (same-origin /api/ calls)

The frontend calls /api/* on the same domain. In development, Vite's dev server runs the frontend, and the serverless functions run locally via Vercel CLI (vercel dev).

For production, Vercel serves both the static frontend and the serverless functions from one deployment.

Deploy

Push to GitHub and connect the repo to Vercel. Set:

• Root Directory: frontend
• Environment Variable: ETHERSCAN_API_KEY

API

POST /api/check-address

{ "address": "0x165CD37b4C644C2921454429E7F9358d18A45e14" }

{
  "success": true,
  "data": {
    "address": "0x165cd37b4c644c2921454429e7f9358d18a45e14",
    "verdict": "CLEAN",
    "risk_score": 10,
    "findings": ["High transaction volume with low value"],
    "transaction_count": 78958,
    "total_value": "348.57",
    "recommendation": "No suspicious activity detected",
    "blockchain": "ethereum",
    "balance": "157955776415709087"
  }
}

Blacklist Hit

If the address is found in the ScamSniffer database:

{
  "success": true,
  "data": {
    "verdict": "MALICIOUS",
    "risk_score": 100,
    "findings": ["Address found in ScamSniffer scam database"],
    "blacklistInfo": { "source": "scamsniffer" }
  }
}

License

MIT