feat: Transactions package

packages/transactions/.eslintrc.js

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+/* eslint-env node */
+
+// @ts-check
+
+const { defineConfig } = require("eslint-define-config");
+
+module.exports = defineConfig({
+  extends: ["../../.eslintrc.js"],
+  overrides: [
+    {
+      files: ["tsup.config.ts"],
+      rules: {
+        "import/no-extraneous-dependencies": "off",
+      },
+    },
+  ],
+});

packages/transactions/README.md

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+# @phantom/transactions
+
+A multi-chain transaction builder package that simplifies transaction creation for dApp development with Phantom Wallet SDK. Build transactions for Solana, Ethereum, and other blockchains with a unified API.
+
+## Installation
+
+```bash
+npm install @phantom/transactions
+# or
+yarn add @phantom/transactions
+```
+
+## Overview
+
+The `@phantom/transactions` package provides a simple, unified interface for creating transactions across multiple blockchains. It automatically handles chain-specific logic while providing a consistent developer experience.
+
+### Supported Networks
+
+- **Solana**: Native SOL transfers and SPL tokens
+- **Ethereum/EVM**: Native ETH transfers and ERC-20 tokens
+  - Ethereum, Polygon, Arbitrum, Optimism, Base, BSC, Avalanche
+- **Bitcoin**: Native BTC transfers (coming soon)
+- **Sui**: Native SUI transfers and tokens (coming soon)
+
+## Quick Start
+
+```typescript
+import { createSendTokenTransaction } from "@phantom/transactions";
+import { useSignAndSendTransaction, NetworkId } from "@phantom/react-sdk";
+
+function SendToken() {
+  const { signAndSendTransaction } = useSignAndSendTransaction();
+
+  const handleSend = async () => {
+    // Create transaction
+    const { transaction, error } = await createSendTokenTransaction({
+      networkId: NetworkId.SOLANA_MAINNET,
+      from: "sender-address",
+      to: "recipient-address", 
+      amount: "1.5", // 1.5 SOL
+    });
+
+    if (error) {
+      console.error("Transaction creation failed:", error);
+      return;
+    }
+
+    // Sign and send with Phantom SDK
+    const signature = await signAndSendTransaction({
+      transaction,
+      networkId: NetworkId.SOLANA_MAINNET,
+    });
+  };
+
+  return <button onClick={handleSend}>Send 1.5 SOL</button>;
+}
+```
+
+## API Reference
+
+### createSendTokenTransaction(params)
+
+Creates a transaction for sending tokens on any supported blockchain.
+
+**Parameters:**
+- `networkId` (NetworkId) - The target network identifier
+- `from` (string) - Sender address
+- `to` (string) - Recipient address  
+- `amount` (string | number | bigint) - Amount to send
+- `token?` (string) - Token contract address (optional for native transfers)
+- `decimals?` (number) - Token decimals (auto-detected if not provided)
+
+**Returns:**
+- `Promise<TransactionResult>` with:
+  - `transaction` - The blockchain-specific transaction object
+  - `error?` - Error message if transaction creation failed
+
+## Usage Examples
+
+### Native Token Transfers
+
+```typescript
+import { createSendTokenTransaction, NetworkId } from "@phantom/transactions";
+
+// Send SOL on Solana
+const { transaction, error } = await createSendTokenTransaction({
+  networkId: NetworkId.SOLANA_MAINNET,
+  from: "sender-solana-address",
+  to: "recipient-solana-address",
+  amount: "0.1", // 0.1 SOL
+});
+
+// Send ETH on Ethereum
+const { transaction, error } = await createSendTokenTransaction({
+  networkId: NetworkId.ETHEREUM_MAINNET,
+  from: "0x...", // sender address
+  to: "0x...", // recipient address
+  amount: "0.05", // 0.05 ETH
+});
+
+// Send MATIC on Polygon
+const { transaction, error } = await createSendTokenTransaction({
+  networkId: NetworkId.POLYGON_MAINNET,
+  from: "0x...",
+  to: "0x...",
+  amount: "10", // 10 MATIC
+});
+```
+
+### Token Transfers
+
+```typescript
+// Send USDC on Solana (SPL Token)
+const { transaction, error } = await createSendTokenTransaction({
+  networkId: NetworkId.SOLANA_MAINNET,
+  from: "sender-address",
+  to: "recipient-address",
+  amount: "100", // 100 USDC
+  token: "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v", // USDC mint address
+  decimals: 6, // USDC has 6 decimals
+});
+
+// Send USDC on Ethereum (ERC-20)
+const { transaction, error } = await createSendTokenTransaction({
+  networkId: NetworkId.ETHEREUM_MAINNET,
+  from: "0x...",
+  to: "0x...",
+  amount: "50",
+  token: "0xA0b86a33E6441E52bB62c678b9431B57e4FB3b3A", // USDC contract address
+  decimals: 6,
+});
+```
+
+### Convenience Functions
+
+```typescript
+import { createNativeTransfer, createTokenTransfer } from "@phantom/transactions";
+
+// Native transfer (convenience function)
+const { transaction } = await createNativeTransfer({
+  networkId: NetworkId.SOLANA_DEVNET,
+  from: "sender",
+  to: "recipient", 
+  amount: "2.0",
+});
+
+// Token transfer (convenience function)
+const { transaction } = await createTokenTransfer({
+  networkId: NetworkId.ETHEREUM_MAINNET,
+  from: "0x...",
+  to: "0x...",
+  amount: "1000",
+  token: "0x...", // Required for token transfers
+  decimals: 18,
+});
+```
+
+## RPC Configuration
+
+Configure custom RPC endpoints for different networks:
+
+```typescript
+import { setRPCConfig, getRPCConfig } from "@phantom/transactions";
+
+// Set custom RPC endpoints
+setRPCConfig({
+  solana: {
+    mainnet: "https://your-solana-rpc.com",
+    devnet: "https://your-solana-devnet.com",
+  },
+  ethereum: {
+    mainnet: "https://your-ethereum-rpc.com",
+    sepolia: "https://your-sepolia-rpc.com",
+  },
+  polygon: {
+    mainnet: "https://your-polygon-rpc.com",
+  },
+});
+
+// Get current configuration
+const config = getRPCConfig();
+console.log(config.solana?.mainnet);
+```
+
+### Environment Variables
+
+You can also configure RPC endpoints via environment variables:
+
+```bash
+# Solana
+SOLANA_MAINNET_RPC=https://api.mainnet-beta.solana.com
+SOLANA_DEVNET_RPC=https://api.devnet.solana.com
+
+# Ethereum
+ETHEREUM_MAINNET_RPC=https://mainnet.infura.io/v3/YOUR_KEY
+ETHEREUM_SEPOLIA_RPC=https://sepolia.infura.io/v3/YOUR_KEY
+
+# Polygon
+POLYGON_MAINNET_RPC=https://polygon-mainnet.infura.io/v3/YOUR_KEY
+
+# Other networks...
+```
+
+## Integration with Phantom SDKs
+
+### React SDK Integration
+
+```typescript
+import { createSendTokenTransaction } from "@phantom/transactions";
+import { useSignAndSendTransaction, NetworkId } from "@phantom/react-sdk";
+
+function TokenSender() {
+  const { signAndSendTransaction, loading } = useSignAndSendTransaction();
+
+  const sendUSDC = async () => {
+    const { transaction, error } = await createSendTokenTransaction({
+      networkId: NetworkId.SOLANA_MAINNET,
+      from: "your-address",
+      to: "recipient-address",
+      amount: "10",
+      token: "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
+    });
+
+    if (error) {
+      alert(error);
+      return;
+    }
+
+    try {
+      const signature = await signAndSendTransaction({
+        transaction,
+        networkId: NetworkId.SOLANA_MAINNET,
+      });
+      console.log("Transaction sent:", signature);
+    } catch (err) {
+      console.error("Failed to send:", err);
+    }
+  };
+
+  return (
+    <button onClick={sendUSDC} disabled={loading}>
+      Send 10 USDC
+    </button>
+  );
+}
+```
+
+### Server SDK Integration
+
+```typescript
+import { createSendTokenTransaction } from "@phantom/transactions";
+import { ServerSDK, NetworkId } from "@phantom/server-sdk";
+
+const sdk = new ServerSDK({
+  organizationId: process.env.ORGANIZATION_ID!,
+  apiPrivateKey: process.env.PRIVATE_KEY!,
+  apiBaseUrl: process.env.API_URL!,
+});
+
+async function serverSideTransfer(walletId: string) {
+  // Create transaction
+  const { transaction, error } = await createSendTokenTransaction({
+    networkId: NetworkId.ETHEREUM_MAINNET,
+    from: "wallet-address",
+    to: "0x742d35Cc6634C0532925a3b8D4C8db86fB5C4A7E",
+    amount: "0.1", // 0.1 ETH
+  });
+
+  if (error) {
+    throw new Error(error);
+  }
+
+  // Sign and send with server SDK
+  const result = await sdk.signAndSendTransaction({
+    walletId,
+    transaction,
+    networkId: NetworkId.ETHEREUM_MAINNET,
+  });
+
+  return result;
+}
+```
+
+## Error Handling
+
+```typescript
+const { transaction, error } = await createSendTokenTransaction({
+  networkId: NetworkId.SOLANA_MAINNET,
+  from: "invalid-address",
+  to: "recipient",
+  amount: "1.0",
+});
+
+if (error) {
+  console.error("Transaction creation failed:", error);
+  // Handle specific error cases
+  if (error.includes("Invalid address")) {
+    // Handle invalid address
+  } else if (error.includes("Insufficient")) {
+    // Handle insufficient balance
+  }
+  return;
+}
+
+// Transaction created successfully
+console.log("Transaction ready:", transaction);
+```
+
+## Network Support
+
+| Network | Native Token | Custom Tokens | Status |
+|---------|-------------|---------------|---------|
+| Solana | ✅ SOL | 🚧 SPL Tokens | Partial |
+| Ethereum | ✅ ETH | 🚧 ERC-20 | Partial |
+| Polygon | ✅ MATIC | 🚧 ERC-20 | Partial |
+| Arbitrum | ✅ ETH | 🚧 ERC-20 | Partial |
+| Optimism | ✅ ETH | 🚧 ERC-20 | Partial |
+| Base | ✅ ETH | 🚧 ERC-20 | Partial |
+| BSC | ✅ BNB | 🚧 BEP-20 | Partial |
+| Avalanche | ✅ AVAX | 🚧 ERC-20 | Partial |
+| Bitcoin | 🚧 BTC | ❌ | Coming Soon |
+| Sui | 🚧 SUI | 🚧 Sui Tokens | Coming Soon |
+
+## Development Status
+
+This package is in active development. Current limitations:
+
+- **SPL Token transfers**: Need @solana/spl-token implementation
+- **ERC-20 transfers**: Need proper contract call encoding
+- **Bitcoin**: Full implementation needed
+- **Sui tokens**: Token-specific logic needed
+
+## Contributing
+
+This package is part of the Phantom Wallet SDK monorepo. Contributions are welcome!
+
+```bash
+# Install dependencies
+yarn install
+
+# Build the package
+yarn workspace @phantom/transactions build
+
+# Run tests
+yarn workspace @phantom/transactions test
+
+# Lint code
+yarn workspace @phantom/transactions lint
+```
+
+## License
+
+MIT License - see LICENSE file for details.

packages/transactions/jest.config.js

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+/** @type {import('jest').Config} */
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  roots: ['<rootDir>/src'],
+  testMatch: ['**/__tests__/**/*.ts', '**/?(*.)+(spec|test).ts'],
+  transform: {
+    '^.+\\.ts$': 'ts-jest',
+  },
+  collectCoverageFrom: [
+    'src/**/*.ts',
+    '!src/**/*.d.ts',
+    '!src/**/*.test.ts',
+  ],
+  moduleNameMapping: {
+    '^@phantom/(.*)$': '<rootDir>/../$1/src',
+  },
+  testTimeout: 10000,
+};