ERC-5114

Smart Contract Standard

Soulbound Badge standard defining non-transferable tokens that are permanently bound to a specific ERC-721 NFT (persona) at the time of minting. Neither the holder nor the minter may transfer or revoke the badge after issuance. Designed for persistent, censorship-resistant credential and reputation attestation attached to on-chain identities rather than wallet addresses.

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Details

License https://github.com/ethereum/EIPs/blob/master/EIPS/eip-5114.md
Dev Status 🏁 Final
Dev Status Detail Review (pending Final)
Owner Micah Zoltu
Country Global / Decentralized
Start Year 2022
Stack Solidity / EVM; requires ERC-721 for the target NFT persona; collectionUri and badgeUri must point to immutable content-addressable resources
Funding Volunteer / individual author contribution
Last Investigated Mar 9, 2026

Use Case Domains

Identity & Trust

Affordances

Portable attestations

Smart Contract Standard Attributes

Origins Proposed by Micah Zoltu on May 30, 2022, inspired by Vitalik Buterin, E. Glen Weyl, and Puja Ohlhaver's 'Decentralized Society: Finding Web3's Soul' paper (May 2022), which theorized non-transferable 'soulbound' tokens for on-chain identity and reputation. ERC-5114 specifically binds badges to NFT personas rather than EOA wallets, enabling portable identity through NFT transfers.
Data Formats Mint event: (badgeId, nftAddress, nftTokenId); collectionUri() and badgeUri(uint256) returning immutable URIs; metadataFormat() for data format versioning; content-addressable (e.g., IPFS CID) URIs strongly recommended
Terms CC0
Funds Unknown
Based On ERC-721 (target NFT persona); conceptually derived from Buterin/Weyl/Ohlhaver 'Decentralized Society' paper (2022)
Permissions Permissionless minting (any contract may issue badges); post-mint transfer is unconditionally blocked; no admin revocation — immutability is a core design invariant
Development Tools OpenZeppelin Contracts (custom extension); Hardhat; Foundry; standard EVM tooling
Protocol Maturity / Standardization Review status; not yet Final; conceptual adoption is strong but competing standards (ERC-5484 Consensual SBT, ERC-4973 Account-Bound Tokens) create ecosystem fragmentation
Trust Framework Immutability as trust: badge issuance is on-chain and permanent; content-addressable URIs prevent post-hoc metadata manipulation; trust derives from the issuing contract's identity and reputation rather than a central registry
Target Application Domain Civic participation credentials; DAO membership and contribution records; educational and professional certifications; reputation badges; attendance proofs; KYC attestations; voter eligibility records
Deployment Model Per-issuer badge contract deployed independently; badges bound to any target ERC-721 persona at mint time
Standard Type Token Standard / Identity Standard
Ecosystem Ethereum (EVM-compatible chains)