DMANDATE - Decentralized Recurring Payments on Solana

DMANDATE is a Solana-based protocol for decentralized recurring payments. Users pre-approve a PDA to transfer tokens (e.g., USDC) without locking funds. A backend processes payments at scheduled intervals, ensuring self-custody and transparency. Ideal for subscriptions, salaries, and bills, DMANDATE offers a trustless, non-custodial alternative to traditional e-mandates.

DEVNET ADDRESS - BXXJENjyLn4ZGYfkDpSxZ6Vt7TcxW7BQJgWaGiQGbfed

In action

DMANDATE CAPSTONE - Watch Video

Table of Contents

• Features
• Repository Structure
• Smart Contract
• Backend Mandate Processor
• CLI Tool
• Installation & Setup
• Development
• Testing
• Deployment

Features

• Non-custodial recurring payments: Users maintain control of their funds at all times
• Programmable payment schedules: Set custom frequencies for payment execution
• Transparent on-chain history: All payments and mandates are recorded on the Solana blockchain
• Automated payment processing: Backend service checks and executes due payments
• User-friendly CLI: Command-line interface for managing mandates and payments
• Web3 friendly: Built natively for Solana's SPL tokens

Repository Structure

dmandate/
├── backend/             # Backend payment processor service
│   ├── idl/             # Anchor IDL for the dmandate program
│   └── src/             # Source code for the mandate processor
├── cli/                 # Command-line interface tool
├── programs/            # Solana smart contracts written in Rust
│   └── dmandate/        # Main dmandate program
└── tests/               # Integration tests for the program

Smart Contract

The DMANDATE smart contract is built using the Anchor framework and includes the following key instructions:

• register_user: Registers a user in the system
• create_mandate: Creates a new recurring payment mandate
• execute_payment: Executes a payment for an active mandate
• cancel_mandate: Cancels an active mandate
• reapprove_mandate: Updates the approval amount for an existing mandate
• close_payment_history: Closes a payment history record to reclaim rent

Backend Mandate Processor

The backend service monitors active mandates on the Solana blockchain and automatically executes payments when they are due.

Features

• Periodic checking of all active mandates
• Automatic payment execution for due mandates
• Error handling for failed payments
• Configurable settings via environment variables or config file
• Logging of all operations

Configuration

The mandate processor can be configured with the following options:

Option	Environment Variable	Description	Default
Check Interval	CHECK_INTERVAL	How often to check for payable mandates (ms)	60000 (1 min)
RPC URL	RPC_URL	Solana RPC URL	http://localhost:8899
Keypair Path	KEYPAIR_PATH	Path to keypair JSON file	~/.config/solana/id.json
Program ID	PROGRAM_ID	DMANDATE program ID	BXXJENjyLn4ZGYfkDpSxZ6Vt7TcxW7BQJgWaGiQGbfed
Batch Size	BATCH_SIZE	Max mandates to process in one batch	100
Buffer Time	BUFFER_TIME	Time buffer before scheduled payment (seconds)	60
Log Level	LOG_LEVEL	Logging level (debug, info, warn, error)	info
Notifications	ENABLE_NOTIFICATIONS	Enable payment notifications	false

CLI Tool

The DMANDATE CLI tool provides a convenient way to interact with the smart contract.

See the CLI README for detailed usage instructions.

Installation & Setup

Prerequisites

• Node.js v14+ and npm
• Rust and Cargo
• Solana CLI tools
• Anchor Framework

Setting Up the Project

1. Clone the repository:

   git clone https://github.com/yourusername/dmandate.git
   cd dmandate

2. Install dependencies:

   npm install

3. Build the Solana program:

   anchor build

4. Generate the program ID (if needed):

   solana-keygen new -o target/deploy/dmandate-keypair.json
   anchor keys list

   Update the program ID in Anchor.toml and lib.rs

5. Setup the backend processor:

   cd backend
   npm install

6. Setup the CLI:

   cd cli
   npm install
   npm link  # Optional, to use CLI globally

7. Create a .env file in the backend directory:

   RPC_URL=https://api.devnet.solana.com
   KEYPAIR_PATH=/path/to/your/keypair.json
   CHECK_INTERVAL=60000
   BUFFER_TIME=60
   LOG_LEVEL=info
   

Running the Mandate Processor

cd backend
npm run build
node dist/index.js

Or use a process manager like PM2:

npm install -g pm2
pm2 start dist/index.js --name mandate-processor

Development

Local Development Environment

1. Start a local Solana validator:

   solana-test-validator

2. Deploy the program to the local network:

   anchor deploy

3. Run the mandate processor against local network:

   cd backend
   RPC_URL=http://localhost:8899 npm run start

Making Changes to the Smart Contract

1. Modify code in programs/dmandate/src/
2. Build with anchor build
3. Update IDL if needed: anchor idl parse -f programs/dmandate/src/lib.rs -o target/idl/dmandate.json
4. Copy the new IDL to the backend: cp target/idl/dmandate.json backend/idl/
5. Deploy: anchor deploy

Testing

Smart Contract Tests

Run the test suite:

anchor test

Backend Tests

cd backend
npm test

Deployment

Program Deployment

1. Build the program:

   anchor build

2. Deploy to your desired network:

   anchor deploy --provider.cluster devnet  # For devnet
   # OR
   anchor deploy --provider.cluster mainnet  # For mainnet

3. Verify the program ID and update configuration as needed.

Backend Deployment

1. Build the backend:

   cd backend
   npm run build

2. Deploy using your preferred method (PM2, Docker, cloud services).

3. Make sure to set the appropriate environment variables for your deployment.

License

MIT License