ChainDrop

Reverse Onboarding for Blockchain Value Delivery

Send crypto to anyone, anywhere — no wallet required

Overview • How It Works • Architecture • Quick Start • Documentation

Overview

ChainDrop is a gasless payment protocol built on Ethereum Account Abstraction (ERC-4337) that enables users to send digital assets using email addresses, phone numbers, or social handles — without requiring recipients to create a wallet, manage seed phrases, or pre-fund gas fees.

The Problem

Blockchain systems enforce a rigid, identity-first lifecycle:

User creates a wallet
User secures private keys
User acquires native gas tokens
User receives value
User interacts with applications

This creates severe friction. Studies show onboarding drop-off rates exceed 80%, limiting blockchain adoption to technically sophisticated users.

The Solution: Reverse Onboarding

ChainDrop inverts the traditional lifecycle to a value-first model:

Traditional:  Account → Identity → Value
ChainDrop:    Value → Account → Identity

Recipients receive funds before creating a wallet. Wallet creation happens automatically when they claim, with transaction costs deducted directly from the transferred amount.

Key Features

For Recipients

Zero Setup Required — Receive crypto without creating a wallet first
100% Gasless — No need to acquire CRO or understand gas fees
Social Identifiers — Claim using email, phone, or Twitter instead of 0x addresses
Instant Onboarding — Embedded wallet created automatically with Privy
Non-Custodial — Full ownership from the moment of claim
Email Notifications — Get notified instantly when someone sends you crypto

For Senders

Familiar UX — Send to user@email.com instead of 0x742d35Cc...
Multi-Asset Support — Send CRO or any ERC-20 token (USDC, USDT, etc.)
Self-Funded Transactions — No ongoing platform subsidies required
One-Click Sharing — Generate claim links automatically shared via email
Transfer Tracking — Monitor pending and claimed transfers easily
AI Payment Agents — Create autonomous agents that send payments based on triggers

Technical Innovation

Ghost Vaults — Counterfactual addresses that receive funds before deployment
CREATE2 Determinism — Pre-computed addresses using EIP-1014
Atomic Reimbursement — Self-funding deployment without external subsidies
ERC-4337 Compliant — Full Account Abstraction compatibility
Modular Identity — Pluggable verifiers for privacy and flexibility
AI Payment Automation — Claude-powered agents for scheduled and conditional payments

✨ Featured Capabilities

1. Social Identity Payments

Send crypto using email addresses, phone numbers, or Twitter handles. Recipients don't need a wallet — it's created automatically when they claim.

2. Email Notifications 📧

Recipients receive beautiful HTML email notifications when someone sends them crypto, with:

Instant notification when transfer is sent
One-click claim link
Confirmation email after successful claim
Transaction details and explorer links

3. AI Payment Agents 🤖

Create autonomous payment agents powered by Claude that can:

Schedule recurring payments (daily, weekly, monthly)
Trigger payments based on conditions (e.g., "Pay $100 to alice@example.com every Monday")
Automate payroll, subscriptions, and rewards
Execute complex payment logic without manual intervention

4. Embedded Wallets via Privy

Social login (Email, Twitter, Phone)
Automatic wallet creation
No seed phrases to manage
Export to MetaMask/other wallets
Fully non-custodial

5. Beautiful Modern UI

Gradient design with Cronos brand colors
Responsive mobile-first layout
Smooth animations and transitions
Real-time balance updates
Transaction history and pending claims

How It Works

The Flow

sequenceDiagram
    participant Sender
    participant ChainDrop API
    participant Ghost Vault
    participant Recipient
    participant Bundler
    participant EntryPoint
    participant Smart Account

    Sender->>ChainDrop API: Send $50 USDC to user@email.com
    ChainDrop API->>Ghost Vault: Compute counterfactual address (CREATE2)
    Sender->>Ghost Vault: Transfer $50 USDC
    ChainDrop API->>Recipient: Share claim link via email

    Note over Ghost Vault: Vault holds funds<br/>(no code deployed yet)

    Recipient->>ChainDrop API: Click claim link + authenticate
    ChainDrop API->>Bundler: Submit UserOperation
    Bundler->>EntryPoint: Execute UserOp
    EntryPoint->>Ghost Vault: Deploy smart account at address
    Ghost Vault->>Smart Account: Transform into full account
    Smart Account->>Recipient: Transfer $49.50 USDC (after fees)
    Smart Account->>Bundler: Reimburse gas from claim amount

Step-by-Step

Sender Initiates Transfer
- Enters recipient identifier (e.g., alice@example.com)
- Specifies amount and token (e.g., 50 USDC)
- ChainDrop computes deterministic address using CREATE2
- Funds sent to "Ghost Vault" (address with no deployed code)
Recipient Receives Notification
- Gets claim link via email/SMS
- No wallet or blockchain knowledge required
- Link contains secure claim token
Recipient Claims
- Authenticates using email/social account
- ChainDrop generates claim proof
- UserOperation submitted to ERC-4337 bundler
Atomic Deployment & Reimbursement
- Smart account deployed at Ghost Vault address
- Funds transfer to recipient's control
- Gas costs reimbursed from claim amount
- All steps execute atomically (success or full revert)
Result
- Recipient has a fully-featured smart account
- Funds available immediately
- Zero gas spent by recipient
- Self-sustaining economics (no ongoing subsidies)

Architecture

Core Components

Smart Contracts (`/contracts/contracts/core/`)

Contract	Purpose	Key Features
AccountFactory.sol	Creates deterministic smart accounts	Uses CREATE2 for counterfactual addressing Generates salts from hashed identifiers Deploys ERC-1967 proxy contracts
SimpleAccount.sol	ERC-4337 compliant smart account	Receives funds before deployment Implements secure claim verification Prevents double-claiming Supports session keys & social recovery
ChainDropPaymaster.sol	Sponsors gas for claim transactions	Validates UserOperations Charges configurable fee (0.5-1%) Reimburses bundlers atomically
ClaimVerifier.sol	Cryptographic claim validation	Generates verifiable proofs Hashes identifiers for privacy ECDSA signature recovery

Backend API (`/backend/src/`)

├── controllers/
│   ├── transferController.js    # HTTP request handlers for transfers
│   └── agentController.js       # HTTP request handlers for AI agents
├── services/
│   ├── transferService.js       # Business logic (create, claim, verify)
│   ├── blockchainService.js     # Smart contract interactions
│   ├── emailService.js          # Email notifications via Resend
│   └── agentService.js          # AI agent management and execution
├── db/
│   └── schema.js                # PostgreSQL schema (transfers, claims, agents)
└── routes/
    └── index.js                 # API route definitions

Frontend App (`/frontend/src/`)

├── pages/
│   ├── HomePage.jsx             # Landing page with feature showcase
│   ├── SendPage.jsx             # Send crypto interface
│   ├── ClaimPage.jsx            # Claim funds page
│   ├── WalletPage.jsx           # Wallet dashboard
│   └── AgentsPage.jsx           # AI agent management + AI chat
├── components/
│   ├── Navigation.jsx           # Reusable navigation bar
│   └── AIChat.jsx               # AI payment assistant chat interface
└── index.css                    # Tailwind configuration & custom styles

Technical Stack

Blockchain

Solidity 0.8.28 with Cancun EVM optimizations
Hardhat development framework
OpenZeppelin Contracts v5.4.0
Account Abstraction (ERC-4337) v0.8.0
Cronos Testnet (Chain ID: 338)

Backend

Node.js + Express.js v5.2.1
SQLite + Drizzle ORM v0.45.1 (PostgreSQL ready for production)
ethers.js v6.16.0 for blockchain interaction
Resend for email notifications
Anthropic Claude API for natural language payment parsing
Crypto.com AI Agent SDK for blockchain operations

Frontend

React 19 + Vite 7
Privy for embedded wallet authentication
TailwindCSS v4 with custom Cronos theme
React Router v7 for navigation
Beautiful gradient UI with responsive design
AI chat interface for natural language payments

Ghost Vaults: The Core Innovation

A Ghost Vault is a counterfactual smart account that:

Exists before deployment — Address computed deterministically via CREATE2
Receives funds trustlessly — Ethereum state allows balances at non-deployed addresses
Claimable exactly once — Cryptographic proofs prevent unauthorized access
Transforms atomically — Becomes a full smart account upon claim

Deterministic Address Generation

// Pseudocode
salt = keccak256(abi.encodePacked(
    hashedIdentifier,  // e.g., keccak256("user@email.com")
    nonce,             // Prevents collisions
    chainId            // Chain-specific
))

ghostVaultAddress = CREATE2(
    factoryAddress,
    salt,
    keccak256(accountInitCode)
)

This enables:

Push payments — Send funds before recipient setup
Predictable addresses — Same identifier always produces same address
No coordination — Sender and recipient never interact directly

API Documentation

Base URL

https://api.chaindrop.app  (Production - TBD)
http://localhost:3000      (Local Development)

Endpoints

1. Create Transfer

Send funds to an identifier.

POST /api/transfer/send
Content-Type: application/json

{
  "senderAddress": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb",
  "recipientIdentifier": "alice@example.com",
  "amount": "50",
  "token": "USDC"
}

Response:

{
  "success": true,
  "data": {
    "claimToken": "eyJhbGc...",
    "claimLink": "https://chaindrop.app/claim/eyJhbGc...",
    "ghostVaultAddress": "0x9f8b7c6d5e4a3b2c1d0e9f8a7b6c5d4e3f2a1b0c",
    "expiresAt": "2026-01-07T08:00:00Z",
    "estimatedGas": "0.15 USDC"
  }
}

2. Claim Transfer

Claim funds from a Ghost Vault.

POST /api/transfer/claim
Content-Type: application/json

{
  "claimToken": "eyJhbGc...",
  "recipientWalletAddress": "0x1234567890abcdef...",
  "claimProof": "0xsignature..."
}

Response:

{
  "success": true,
  "data": {
    "transactionHash": "0xabc123...",
    "deployedAccountAddress": "0x9f8b7c6d...",
    "claimedAmount": "49.50",
    "gasCostDeducted": "0.50",
    "token": "USDC"
  }
}

3. Estimate Transfer

Get Ghost Vault address and gas estimate before sending.

POST /api/transfer/estimate

{
  "recipientIdentifier": "alice@example.com",
  "amount": "50",
  "token": "USDC"
}

4. Get Transfer Details

GET /api/transfer/:claimToken

5. List Sender Transfers

GET /api/transfer/sender/:senderAddress

6. Platform Statistics

GET /api/transfer/stats

Response:

{
  "totalTransfers": 1247,
  "totalClaimed": 892,
  "totalVolumeUSD": "125000.50",
  "activeGhostVaults": 355,
  "averageClaimTimeHours": 2.3
}

Quick Start

Prerequisites

Node.js v18+
npm or yarn
Cronos Testnet CRO (Faucet)
Resend API key for email notifications (Get one here)

Installation

# Clone repository
git clone https://github.com/Jeremicarose/ChainDrop.git
cd ChainDrop

# Install contract dependencies
cd contracts
npm install

# Install backend dependencies
cd ../backend
npm install

Smart Contract Deployment

cd contracts

# Configure environment
cp .env.example .env
# Edit .env with your Cronos Testnet RPC URL and deployer private key

# Compile contracts
npx hardhat compile

# Run tests
npx hardhat test

# Deploy to Cronos Testnet
npx hardhat run scripts/deploy.js --network cronosTestnet

# Verify contracts (optional)
npx hardhat verify --network cronosTestnet <CONTRACT_ADDRESS>

Backend Setup

cd backend

# Configure environment
cp .env.example .env
# Add:
# - Deployed contract addresses
# - Admin private key
# - Resend API key (get from https://resend.com/api-keys)
# - Database connection string

# Initialize database
npm run db:push

# Start development server
npm run dev

# Production
npm start

Server runs at http://localhost:3000

Frontend Setup

cd frontend

# Install dependencies
npm install

# Configure environment
cp .env.example .env
# Add your Privy App ID

# Start development server
npm run dev

Frontend runs at http://localhost:5173

Testing the Flow

# 1. Send a test transfer
curl -X POST http://localhost:3000/api/transfer/send \
  -H "Content-Type: application/json" \
  -d '{
    "senderAddress": "0xYourAddress",
    "recipientIdentifier": "test@example.com",
    "amount": "10",
    "token": "ETH"
  }'

# 2. Get claim link from response and test claim
curl -X POST http://localhost:3000/api/transfer/claim \
  -H "Content-Type: application/json" \
  -d '{
    "claimToken": "<TOKEN_FROM_STEP_1>",
    "recipientWalletAddress": "0xRecipientAddress"
  }'

Use Cases

Remittances

Send USDC internationally using just a phone number. Recipients claim funds without understanding blockchain, with fees far lower than Western Union or PayPal.

Payroll & Gig Payments

DAOs and companies pay contributors via email addresses. No need to collect wallet addresses or manage onboarding.

Airdrops

Protocols distribute tokens to real identifiers (email/Twitter), reducing bot farming and increasing claim rates from ~5% to ~60%+.

Consumer Applications

Apps deliver immediate value to new signups, funding their first wallet automatically. Users experience value before infrastructure.

Cross-Border B2B Payments

Businesses pay international vendors using familiar identifiers, avoiding SWIFT delays and high fees.

Security Model

Claim Authorization

Cryptographic Proofs: Only authenticated owner of identifier can generate valid claim proof
One-Time Claims: Salts and nonces prevent replay attacks
Atomic Execution: Deployment + claim + reimbursement succeed together or revert entirely
Expiration Protection: 24-hour claim window prevents indefinite fund holding

Address Security

No Squatting: Salts include unpredictable elements (sender nonce + timestamp)
Factory Enforcement: Only valid claims trigger deployment
Deterministic Safety: CREATE2 guarantees address consistency

Relayer Protection

Gas Limits: Strict caps prevent DoS attacks
Rate Limiting: Per-identifier claim frequency restrictions
Decentralized Bundlers: Integration with Pimlico and other bundler networks

Privacy

Hashed Identifiers: On-chain storage uses keccak256(identifier), not plaintext
Off-Chain Verification: Identity providers never hold funds or keys
Future ZK Integration: Zero-knowledge proofs for enhanced privacy (roadmap)

Audits

Smart contracts designed for third-party security audits. Production deployment will undergo formal verification by OpenZeppelin or similar firms.

Economic Model

Self-Sustaining Design

ChainDrop does not rely on ongoing gas subsidies. Each transfer is economically self-contained:

Sender deposits funds to Ghost Vault
Recipient claims → gas deducted from claim amount
Platform fee (0.5-1%) covers operational costs
No external funding required after initial deployment

Fee Structure

Transfer Type	Fee	Who Pays
Individual transfers	0.5-1%	Deducted from claim amount
Enterprise (SaaS)	Flat monthly fee	Sender organization
Airdrops (bulk)	Volume-discounted	Protocol/sender

Comparison with Alternatives

Solution	Ongoing Subsidies?	Sustainable?	Recipient Cost
Traditional Paymasters	Yes (perpetual)	No	Zero (subsidized)
Embedded Wallets	Yes (per-tx)	No	Gas fees required
ChainDrop	No (one-time)	Yes	Zero (self-funded)

Roadmap

Phase 1: MVP ✅ (Completed)

Phase 2: Production Launch (Q1 2026)

SMS notification system
Additional identity verifiers (Worldcoin, OAuth providers)
Security audit by reputable firm
Cronos Mainnet deployment
Initial partnerships (remittance providers, DAOs)

Phase 3: Scale (Q2 2026)

Mobile apps (iOS/Android)
Batch transfer support
Cross-chain bridging (Optimism, Arbitrum, Polygon)
Advanced analytics dashboard
Decentralized bundler network

Phase 4: Ecosystem Expansion (Q3-Q4 2026)

Comparison with Existing Solutions

Feature	Traditional Wallets	Embedded Wallets	Gas-Sponsored Wallets	ChainDrop
Wallet required first	Yes	Yes	Yes	No
Seed phrase management	Required	Optional	Optional	Not needed
Pre-fund gas	Yes	No	No	No
Send to social identifier	No	Limited	Limited	Yes
Self-sustaining economics	N/A	No (subsidies)	No (subsidies)	Yes
Value-before-account	No	No	No	Yes
Claim expiration protection	N/A	No	No	Yes

Contributing

We welcome contributions from the community!

Development Setup

# Fork and clone the repository
git clone https://github.com/<YOUR_USERNAME>/ChainDrop.git
cd ChainDrop

# Create feature branch
git checkout -b feature/your-feature-name

# Make changes and test
npm test

# Commit with conventional commits
git commit -m "feat: add new claim verification method"

# Push and open PR
git push origin feature/your-feature-name

Contribution Guidelines

Follow Solidity style guide for smart contracts
Use ESLint/Prettier for JavaScript
Write tests for new features (aim for >80% coverage)
Update documentation for API changes
Open issues before major refactors

License

This project is licensed under the MIT License - see LICENSE file for details.

Deployed Contracts

Cronos Testnet (Chain ID: 338)

Contract	Address	Explorer
EntryPoint	`0x216e29695D99cEfE8009B7486AD99aC0f5DA2ddd`	View
AccountFactory	`0xD1F80bcFe28F36a66aFcc6eBd0BDD522cD25158C`	View
ChainDropPaymaster	`0x4C6d079F051CfcFB48f32C858E937e51Bb17095c`	View
ClaimVerifier	`0xC40A98006023B7A74e789e3EFc9E82f191eCB619`	View

RPC URL: https://evm-t3.cronos.org Explorer: https://explorer.cronos.org/testnet

Resources

Documentation

Litepaper - Non-technical overview
Getting Started - Quick start guide
API Reference - Complete API documentation
Smart Contract Docs - Contract architecture
System Architecture - Technical deep dive

Links

Website: [Coming Soon]
Blog: [Coming Soon]
Twitter: @ChainDrop (placeholder)
Discord: Join Community (placeholder)
Documentation: docs.chaindrop.app (placeholder)

References

Acknowledgments

ChainDrop builds on foundational work by:

Ethereum Foundation — ERC-4337 Account Abstraction standard
OpenZeppelin — Secure smart contract libraries
Cronos — EVM-compatible blockchain infrastructure
Crypto.com — Cronos ecosystem support
Safe — Smart account reference implementation
Privy — Embedded wallet and authentication
Resend — Modern email API
Anthropic — Claude AI for payment automation

Disclaimer

⚠️ ChainDrop is currently in testnet/MVP phase.

Do not use with real funds on mainnet until full security audit
Smart contracts have not been formally verified
API may change without notice during development
Use at your own risk

This software is provided "as is" without warranty of any kind, express or implied.

Making crypto payments as simple as sending an email

Built with ❤️ for the future of accessible blockchain

⭐ Star us on GitHub • 🐛 Report Bug • 💡 Request Feature

Name		Name	Last commit message	Last commit date
Latest commit History 250 Commits
backend		backend
contracts		contracts
docs		docs
examples		examples
frontend		frontend
.gitignore		.gitignore
.gitignore.contracts		.gitignore.contracts
CHAINDROP_COMPREHENSIVE.md		CHAINDROP_COMPREHENSIVE.md
CONTRIBUTING.md		CONTRIBUTING.md
DEBUGGING.md		DEBUGGING.md
FIXES_APPLIED.md		FIXES_APPLIED.md
GOODBUILDERS_APPLICATION.md		GOODBUILDERS_APPLICATION.md
GoodBuilders 3 - Application Template.md		GoodBuilders 3 - Application Template.md
LICENSE		LICENSE
LITEPAPER.md		LITEPAPER.md
README.md		README.md

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ChainDrop

Reverse Onboarding for Blockchain Value Delivery

Overview

The Problem

The Solution: Reverse Onboarding

Key Features

For Recipients

For Senders

Technical Innovation

✨ Featured Capabilities

1. Social Identity Payments

2. Email Notifications 📧

3. AI Payment Agents 🤖

4. Embedded Wallets via Privy

5. Beautiful Modern UI

How It Works

The Flow

Step-by-Step

Architecture

Core Components

Smart Contracts (/contracts/contracts/core/)

Backend API (/backend/src/)

Frontend App (/frontend/src/)

Technical Stack

Ghost Vaults: The Core Innovation

Deterministic Address Generation

API Documentation

Base URL

Endpoints

1. Create Transfer

2. Claim Transfer

3. Estimate Transfer

4. Get Transfer Details

5. List Sender Transfers

6. Platform Statistics

Quick Start

Prerequisites

Installation

Smart Contract Deployment

Backend Setup

Frontend Setup

Testing the Flow

Use Cases

Remittances

Payroll & Gig Payments

Airdrops

Consumer Applications

Cross-Border B2B Payments

Security Model

Claim Authorization

Address Security

Relayer Protection

Privacy

Audits

Economic Model

Self-Sustaining Design

Fee Structure

Comparison with Alternatives

Roadmap

Phase 1: MVP ✅ (Completed)

Phase 2: Production Launch (Q1 2026)

Phase 3: Scale (Q2 2026)

Phase 4: Ecosystem Expansion (Q3-Q4 2026)

Comparison with Existing Solutions

Contributing

Development Setup

Contribution Guidelines

License

Deployed Contracts

Cronos Testnet (Chain ID: 338)

Resources

Documentation

Links

References

Acknowledgments

Disclaimer

Smart Contracts (`/contracts/contracts/core/`)

Backend API (`/backend/src/`)

Frontend App (`/frontend/src/`)