Skip to content

ERC-6551

ERC-6551: Non-Fungible Token Bound Accounts (TBA)

ERC-6551 is a standard for creating smart contract accounts for each ERC-721 NFT, enabling NFTs to own assets and interact with applications. These accounts are called "Token Bound Accounts" (TBAs).

Problem Addressed

Traditional NFTs are just static digital assets that can only be owned and transferred. They cannot own other tokens (such as ETH or other NFTs), nor can they directly interact with DApps. If you want to "airdrop" assets to an NFT, you typically can only airdrop to the address holding that NFT, not to the NFT itself. ERC-6551 changes this, granting NFTs full "account" capabilities, making them true carriers of on-chain identity.

Mechanism and Principles

ERC-6551 does not modify the existing ERC-721 standard but deploys TBAs through a permissionless Registry. 1. Registry: A factory contract for deploying TBAs for any NFT. 2. Deterministic Addresses: Using the CREATE2 opcode, a TBA's address is determined by the Registry address, ERC-721 contract address, Token ID, Chain ID, and Salt. This means we can know an NFT's corresponding TBA address before actually deploying the contract. 3. Control: A TBA is a smart contract wallet whose control belongs entirely to the current holder of that NFT. When the NFT is transferred, control of the TBA also transfers to the new holder. 4. Implementation Contract: Defines the specific functionality of the TBA (such as executing transactions, receiving assets).

Key Features

  • Backward Compatible: Works with all existing ERC-721 NFTs without upgrading the original contract.
  • Asset Bundling: An NFT can serve as a "backpack" containing ETH, ERC-20 tokens, and even other NFTs. Bundled sales become very simple.
  • On-chain Identity: NFTs can accumulate transaction records, reputation, and social graphs.
  • Multi-chain Support: Can be deployed on all EVM-compatible chains.

Common Use Cases

  • Game Characters (GameFi): An NFT character can own its own equipment (also NFTs) and game tokens. When trading the character, equipment transfers along with it.
  • DAO Membership: NFT-based DAO membership can accumulate voting history and contribution proof.
  • Social Graphs: Social NFTs like Lens Protocol can own their published content and follower relationships.