{
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  "id": "soulbound-tokens",
  "canonical": "https://degreesofsatoshi.com/encyclopedia/soulbound-tokens/",
  "collection": "ethereum",
  "title": "Soulbound tokens: transfer restrictions and issuer powers",
  "description": "Understand non-transferable token designs through ERC-5192 and distinguish locked transfer behavior from trustworthy identity or permanent recovery guarantees.",
  "aliases": [],
  "dates": {
    "published": "2026-10-02",
    "modified": "2026-10-02",
    "verified": "2026-10-02T18:12:41.505Z",
    "dataAsOf": "2026-10-02"
  },
  "authorship": {
    "publisher": "Degrees of Satoshi editorial project",
    "process": "AI-assisted research and drafting with a separate automated source-verification pass; no external expert or named human review is implied."
  },
  "quickAnswer": {
    "text": "“Soulbound token” commonly describes a token designed to be non-transferable. ERC-5192 provides a minimal interface for reporting whether an NFT is locked and requires transfers to fail while locked. It does not by itself prove a person’s identity or define a complete issuance, revocation, privacy or recovery system.",
    "claimId": "soulbound-tokens-quick-answer",
    "sourceIds": [
      "eip5192"
    ]
  },
  "keyFacts": [
    {
      "label": "Signal",
      "value": "locked(tokenId) reports whether the specified token is locked.",
      "sourceIds": [
        "eip5192"
      ],
      "id": "signal",
      "claimId": "soulbound-tokens-fact-signal"
    },
    {
      "label": "Transfer rule",
      "value": "ERC-721 functions that transfer the token between accounts must fail while it is locked.",
      "sourceIds": [
        "eip5192"
      ],
      "id": "transfer-rule",
      "claimId": "soulbound-tokens-fact-transfer-rule"
    },
    {
      "label": "Scope",
      "value": "The standard is a minimal extension, not a universal credential policy.",
      "sourceIds": [
        "eip5192"
      ],
      "id": "scope",
      "claimId": "soulbound-tokens-fact-scope"
    }
  ],
  "prerequisites": [
    "erc-721-nfts"
  ],
  "sections": [
    {
      "id": "credential",
      "heading": "A token can represent an issuer’s assertion",
      "sourceIds": [
        "eip5192"
      ],
      "paragraphs": [
        "A project might use a non-transferable token to represent course completion or membership. The contract can restrict transfer, but the value of the assertion still depends on who issued it and how eligibility was checked.",
        "A blockchain account is not automatically one person. Preventing the token’s transfer does not prove exclusive control of the account’s signing authority."
      ]
    },
    {
      "id": "lifecycle",
      "heading": "Ask about revocation and account loss separately",
      "sourceIds": [
        "eip5192"
      ],
      "paragraphs": [
        "Different implementations may add expiration, burning, revocation or migration policies. The minimal locked interface does not make these policies uniform.",
        "A reader evaluating a credential should identify what happens after a mistake, a compromised key or the issuer’s closure. The “soulbound” label is not a recovery plan."
      ]
    },
    {
      "id": "privacy",
      "heading": "Non-transferability does not make a public claim private",
      "sourceIds": [
        "eip5192",
        "eip721"
      ],
      "paragraphs": [
        "If a token and its ownership are publicly inspectable, others can associate the credential with that account. Metadata may disclose additional information.",
        "Evaluate what is published and whether the subject consented to that disclosure. Transfer restrictions and privacy are different properties."
      ]
    }
  ],
  "faq": [
    {
      "question": "Does a soulbound token prove that an account belongs to one unique human?",
      "answer": "No. The transfer restriction alone does not establish uniqueness, identity or the process used to issue the claim. Those require separate evidence and mechanisms.",
      "sourceIds": [
        "eip5192"
      ]
    }
  ],
  "claims": [
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      "id": "soulbound-tokens-quick-answer",
      "articleSlug": "soulbound-tokens",
      "statement": "“Soulbound token” commonly describes a token designed to be non-transferable. ERC-5192 provides a minimal interface for reporting whether an NFT is locked and requires transfers to fail while locked. It does not by itself prove a person’s identity or define a complete issuance, revocation, privacy or recovery system.",
      "sourceIds": [
        "source-17115c75eee88c85"
      ],
      "sourceLocators": [
        {
          "sourceId": "source-17115c75eee88c85",
          "locator": "Specification"
        }
      ],
      "scope": {
        "collection": "ethereum",
        "dataAsOf": "2026-10-02",
        "blockHeight": null
      },
      "qualification": "",
      "evidenceStatus": "documented",
      "verification": {
        "status": "verified",
        "method": "independent automated source review",
        "checkedAt": "2026-10-02T18:12:41.505Z",
        "reviewer": "Codex independent automated reviewer /root/verify_ethereum_100",
        "notes": [
          "Read ERC-5192 locked interface and exact rule requiring between-account ERC-721 transfers to throw while locked. Tightened key fact to match that scope.",
          "Identity, issuance, account control, recovery and privacy are not provided by the minimal interface; lifecycle alternatives are conditional, not claims of uniform standard behavior."
        ]
      }
    },
    {
      "id": "soulbound-tokens-fact-signal",
      "articleSlug": "soulbound-tokens",
      "statement": "Signal: locked(tokenId) reports whether the specified token is locked.",
      "sourceIds": [
        "source-17115c75eee88c85"
      ],
      "sourceLocators": [
        {
          "sourceId": "source-17115c75eee88c85",
          "locator": "Specification"
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      ],
      "scope": {
        "collection": "ethereum",
        "dataAsOf": "2026-10-02",
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      "qualification": "",
      "evidenceStatus": "documented",
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        "checkedAt": "2026-10-02T18:12:41.505Z",
        "reviewer": "Codex independent automated reviewer /root/verify_ethereum_100",
        "notes": [
          "Read ERC-5192 locked interface and exact rule requiring between-account ERC-721 transfers to throw while locked. Tightened key fact to match that scope.",
          "Identity, issuance, account control, recovery and privacy are not provided by the minimal interface; lifecycle alternatives are conditional, not claims of uniform standard behavior."
        ]
      }
    },
    {
      "id": "soulbound-tokens-fact-transfer-rule",
      "articleSlug": "soulbound-tokens",
      "statement": "Transfer rule: ERC-721 functions that transfer the token between accounts must fail while it is locked.",
      "sourceIds": [
        "source-17115c75eee88c85"
      ],
      "sourceLocators": [
        {
          "sourceId": "source-17115c75eee88c85",
          "locator": "Specification"
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      ],
      "scope": {
        "collection": "ethereum",
        "dataAsOf": "2026-10-02",
        "blockHeight": null
      },
      "qualification": "",
      "evidenceStatus": "documented",
      "verification": {
        "status": "verified",
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        "checkedAt": "2026-10-02T18:12:41.505Z",
        "reviewer": "Codex independent automated reviewer /root/verify_ethereum_100",
        "notes": [
          "Read ERC-5192 locked interface and exact rule requiring between-account ERC-721 transfers to throw while locked. Tightened key fact to match that scope.",
          "Identity, issuance, account control, recovery and privacy are not provided by the minimal interface; lifecycle alternatives are conditional, not claims of uniform standard behavior."
        ]
      }
    },
    {
      "id": "soulbound-tokens-fact-scope",
      "articleSlug": "soulbound-tokens",
      "statement": "Scope: The standard is a minimal extension, not a universal credential policy.",
      "sourceIds": [
        "source-17115c75eee88c85"
      ],
      "sourceLocators": [
        {
          "sourceId": "source-17115c75eee88c85",
          "locator": "Specification"
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      "scope": {
        "collection": "ethereum",
        "dataAsOf": "2026-10-02",
        "blockHeight": null
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      "qualification": "",
      "evidenceStatus": "documented",
      "verification": {
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        "checkedAt": "2026-10-02T18:12:41.505Z",
        "reviewer": "Codex independent automated reviewer /root/verify_ethereum_100",
        "notes": [
          "Read ERC-5192 locked interface and exact rule requiring between-account ERC-721 transfers to throw while locked. Tightened key fact to match that scope.",
          "Identity, issuance, account control, recovery and privacy are not provided by the minimal interface; lifecycle alternatives are conditional, not claims of uniform standard behavior."
        ]
      }
    }
  ],
  "sources": [
    {
      "id": "eip5192",
      "label": "Minimal Soulbound NFTs",
      "publisher": "Ethereum Improvement Proposals",
      "url": "https://eips.ethereum.org/EIPS/eip-5192",
      "locator": "Specification",
      "note": "A minimal locked-token interface; not a universal identity or revocation design.",
      "version": "EIP/ERC-5192; retrieved document hash recorded",
      "checkedAt": "2026-10-02T17:03:42.322Z",
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      "recordId": "source-17115c75eee88c85"
    },
    {
      "id": "eip721",
      "label": "Non-Fungible Token Standard",
      "publisher": "Ethereum Improvement Proposals",
      "url": "https://eips.ethereum.org/EIPS/eip-721",
      "locator": "Specification: ERC721Metadata; Metadata Choices (metadata extension); NFT Identifiers",
      "note": "Optional token metadata interfaces and the distinction between token and external resource.",
      "version": "EIP/ERC-721; retrieved document hash recorded",
      "checkedAt": "2026-10-02T17:03:42.309Z",
      "contentSha256": "bedd672103f3ebb6803ce2bddb33a9ff3d23b08e8e3ae3173b6a5b016f65e2a1",
      "recordId": "source-b08b9aae11ea4085"
    }
  ],
  "related": {
    "articles": [
      "nft-metadata",
      "smart-account-recovery",
      "ethereum-accounts"
    ],
    "dossiers": [],
    "wallets": []
  },
  "revisionHistory": [
    {
      "date": "2026-10-02",
      "kind": "published",
      "summary": "First publication after primary-source research and independent automated verification."
    }
  ],
  "citation": "Degrees of Satoshi editorial project. “Soulbound tokens: transfer restrictions and issuer powers.” Published 2026-10-02; updated 2026-10-02. https://degreesofsatoshi.com/encyclopedia/soulbound-tokens/"
}