Sender MultiSend — Documentation

Overview

Sender MultiSend is a gas-optimised batch token and NFT distribution dApp built on Arc Testnet. It supports Circle USDC & EURC (ERC-20), cirBTC, ERC-721, and ERC-1155 NFTs. A flat protocol fee of 0.001 USDC per recipient applies.

1. Connect to Arc Testnet

Sender runs on Arc Testnet — an EVM-compatible chain. Connecting your wallet on the dashboard will prompt you to add or switch to Arc automatically. To add it manually in MetaMask, use these values:

2. NFT Holdings Feature

The NFT tab shows all ERC-721 and ERC-1155 tokens held by the connected wallet. Data is fetched from the Blockscout API:

GET https://testnet.arcscan.app/api/v2/addresses/{address}/nft/collections
  ?type=ERC-721,ERC-1155

Features:

• Shows NFT name, symbol, and ERC standard badge
• Copy contract address to clipboard with one click
• Lists all owned token IDs (expandable for large collections)
• Auto-refreshes every 60 seconds
• Supports pagination for wallets with many NFTs

3. CSV Format

Upload or paste CSV in this format for token transfers:

wallet_address,amount,token
0x1234...abcd,10.50,USDC
0xabcd...1234,5.00,EURC
0x9876...dcba,1.00,USDC

For NFT bulk send:

contract_address,token_id,amount,standard,recipient_address
0xNFTContract,1,1,ERC721,0xRecipient1
0xNFTContract,42,5,ERC1155,0xRecipient2

• Header row is optional — auto-detected
• Token defaults to USDC if not specified
• Max 200 rows per batch
• Download the Excel template from the Dashboard for a pre-formatted file

4. Security Checklist

• All wallet addresses validated with isAddress() from viem
• Amounts sanitized — only digits and single decimal point allowed
• CSV paste input sanitized against XSS (strips HTML tags, JS URIs, event handlers)
• Max batch size: 200 recipients — enforced in UI and smart contract
• Balance check before execution — insufficient tokens flagged pre-flight
• Smart contract uses custom errors for cheaper gas than require strings
• Ownership secured with OpenZeppelin Ownable (owner-only fee & withdrawals)
• Transaction history read live from Blockscout — nothing stored in the browser

5. Project Architecture

src/
├── app/
│   └── app/
│       ├── page.tsx             # Dashboard (Token + NFT tabs)
│       ├── history/page.tsx     # Transaction history (live from Blockscout)
│       └── docs/page.tsx        # This page
│
├── components/dashboard/        # Recipients table, summary panels, NFT holdings
│
├── lib/
│   ├── blockchain/
│   │   ├── provider.ts          # Arc Testnet viem client
│   │   ├── tokens.ts            # Token registry + formatters
│   │   ├── multisend.ts         # Token batch execution (pull-then-push)
│   │   ├── nft.ts               # NFT batch execution
│   │   └── history.ts           # Blockscout history reader
│   ├── hooks/                   # use-batch-execution, use-nft-execution, ...
│   └── store/                   # Zustand state (in-memory)
│
└── types/                       # Domain TypeScript types

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