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Token Bound Accounts (ERC-6551)

Create smart contract wallets owned by NFTs. Each NFT gets its own address that can hold assets, execute transactions, and interact with other contracts.

Create a TBA for an NFT​

const tba = await urblock.tba.create({
  token_id: "tok_abc123",       // ERC-721 contract
  nft_token_id: "1",            // token ID
  network: "polygon_amoy",
  idempotency_key: "tba-001",
});

console.log(tba.account_address); // deterministic address

Predict Address Before Creation​

const prediction = await urblock.tba.predictAccount("tba_abc123");
console.log(prediction.address); // same deterministic address

Execute a Call​

The NFT owner can execute arbitrary calls from the TBA:

const tx = await urblock.tba.execute("tba_abc123", {
  to: "0xTokenContract...",
  value: "0",
  data: "0xa9059cbb...", // encoded transfer call
  idempotency_key: "tba-exec-001",
});

Batch Execute​

Execute multiple calls in one transaction:

const tx = await urblock.tba.executeBatch("tba_abc123", {
  calls: [
    { to: "0xToken1...", value: "0", data: "0x..." },
    { to: "0xToken2...", value: "0", data: "0x..." },
  ],
  idempotency_key: "tba-batch-001",
});

Query TBA State​

Get the Owning NFT​

const token = await urblock.tba.getToken("tba_abc123");
console.log(token.chain_id);
console.log(token.token_contract);
console.log(token.token_id);

Get Balance​

const balance = await urblock.tba.getBalance("tba_abc123");
console.log(balance.eth_balance); // native token balance in wei

Get State (Nonce)​

const state = await urblock.tba.getState("tba_abc123");
console.log(state.state); // nonce / execution count

Find TBA by NFT​

const tba = await urblock.tba.getByNft("tok_abc123", "1");
console.log(tba.account_address);

Verify Signatures (EIP-1271)​

const result = await urblock.tba.isValidSignature(
  "tba_abc123",
  "0xMessageHash...",
  "0xSignature...",
);
console.log(result.is_valid);

Use Cases​

  • NFT inventory — NFTs that own other NFTs and tokens
  • On-chain identity — a portable wallet tied to a profile NFT
  • Gaming — characters with their own inventories and balances
  • DAOs — NFT-gated treasury management

Next Steps​