bankr-dev-arbitrary-transactions

name	Bankr Dev - Arbitrary Transactions
description	This skill should be used when building apps that submit raw EVM transactions, custom contract calls, or need to execute pre-built calldata through Bankr. Covers JSON format, validation, and integration patterns.
version	1.0.0

Arbitrary Transaction Capability

Submit raw EVM transactions with explicit calldata via the Bankr API.

What You Can Do

Operation	Description
Submit calldata	Execute pre-built calldata on any supported chain
Custom contract calls	Interact with any contract using raw function calls
Value transfers with data	Send ETH/MATIC while executing calldata

JSON Schema

{
  "to": "0x...",
  "data": "0x...",
  "value": "0",
  "chainId": 8453
}

Field	Type	Required	Description
to	string	Yes	Contract address (0x + 40 hex chars)
data	string	Yes	Calldata (0x + hex, or "0x" for empty)
value	string	Yes	Wei amount as string
chainId	number	Yes	Target chain (1, 137, or 8453)

Supported Chains

Chain	Chain ID
Ethereum	1
Polygon	137
Base	8453
Unichain	130

Usage

import { execute } from "./bankr-client";

// Submit arbitrary transaction
const txJson = {
  to: "0x1234567890abcdef1234567890abcdef12345678",
  data: "0xa9059cbb...",
  value: "0",
  chainId: 8453
};

await execute(`Submit this transaction: ${JSON.stringify(txJson)}`);

Integration Pattern

import { execute } from "./bankr-client";

interface ArbitraryTx {
  to: string;
  data: string;
  value: string;
  chainId: number;
}

async function submitArbitraryTx(tx: ArbitraryTx): Promise<void> {
  // Validate before submission
  if (!tx.to.match(/^0x[a-fA-F0-9]{40}$/)) {
    throw new Error("Invalid address format");
  }
  if (!tx.data.startsWith("0x")) {
    throw new Error("Calldata must start with 0x");
  }
  if (![1, 137, 8453, 130].includes(tx.chainId)) {
    throw new Error("Unsupported chain");
  }

  const prompt = `Submit this transaction: ${JSON.stringify(tx)}`;
  await execute(prompt);
}

// Example: ERC-20 transfer
await submitArbitraryTx({
  to: "0xTokenContractAddress...",
  data: "0xa9059cbb000000000000000000000000...", // transfer(address,uint256)
  value: "0",
  chainId: 8453
});

Error Handling

try {
  await submitArbitraryTx(tx);
} catch (error) {
  if (error.message.includes("reverted")) {
    // Transaction reverted - check calldata encoding
    console.error("Transaction reverted:", error);
  } else if (error.message.includes("insufficient")) {
    // Not enough funds for gas + value
    console.error("Insufficient funds:", error);
  } else if (error.message.includes("unsupported")) {
    // Chain not supported
    console.error("Unsupported chain:", error);
  }
}

Related Skills

• bankr-client-patterns - Client setup and execute function
• bankr-api-basics - API fundamentals
• bankr-token-trading - Higher-level trading operations