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The PoH issuer provides endpoints that issue proof-of-human (PoH) credentials. The main endpoint is credential refresh, which re-issues a PoH credential using a Personal Custody Package (PCP) or a credential-only refresh flow.
Base URL is environment-specific and served by the signup-service app-api. Contact your World ID point of contact for environment endpoints and access.
The refresh endpoint is intended for World ID v3 holders to obtain v4 PoH credentials. It is not a general re-issuance endpoint for v4 holders.

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Credential refresh

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method
POST
/api/v1/refresh
Content-Type: multipart/form-data

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Request

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Headers

HeaderTypeRequiredDescription
x-zkp-proofstringyesBase64-encoded ZKP string containing idCommitment and sub.

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Query parameters

QueryTypeRequiredDescription
idCommstringyesUser identity commitment.

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Form fields (always required)

FieldTypeRequiredDescription
substringyesUser account ID (hex with 0x prefix). Must match previous refreshes for this idComm.
encrypted_user_idstringnoTemporary field while operator rewards depend on it.

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PCP form fields (required only when submitting a PCP)

Include all fields below when refreshing with a Personal Custody Package.
FieldTypeDescription
signup_idstringSignup ID.
signup_id_saltstringSignup ID salt.
orb_idstringOrb ID.
orb_id_saltstringOrb ID salt.
operator_idstringOperator ID.
operator_id_saltstringOperator ID salt.
signup_reasonstringSignup reason.
signup_reason_saltstringSignup reason salt.
timestampstringTimestamp.
timestamp_saltstringTimestamp salt.
software_versionstringSoftware version.
software_version_saltstringSoftware version salt.
orb_countrystringOrb country.
orb_country_saltstringOrb country salt.
iris_code_shares_0stringIris code share 0.
iris_code_shares_1stringIris code share 1.
iris_code_shares_2stringIris code share 2.
hashes.jsonfilePCP hashes JSON file.
hashes.signfilePCP hashes signature file.

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Example (credential-only refresh)

curl -X POST "https://<app-api-host>/api/v1/refresh?idComm=0xabc123..." \
  -H "x-zkp-proof: <base64-zkp>" \
  -F "sub=0x1a2b3c"

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Example (refresh with PCP)

curl -X POST "https://<app-api-host>/api/v1/refresh?idComm=0xabc123..." \
  -H "x-zkp-proof: <base64-zkp>" \
  -F "sub=0x1a2b3c" \
  -F "signup_id=signup_123" \
  -F "signup_id_salt=..." \
  -F "orb_id=orb_abc" \
  -F "orb_id_salt=..." \
  -F "operator_id=operator_123" \
  -F "operator_id_salt=..." \
  -F "signup_reason=..." \
  -F "signup_reason_salt=..." \
  -F "timestamp=1700000000" \
  -F "timestamp_salt=..." \
  -F "software_version=1.2.3" \
  -F "software_version_salt=..." \
  -F "orb_country=US" \
  -F "orb_country_salt=..." \
  -F "iris_code_shares_0=..." \
  -F "iris_code_shares_1=..." \
  -F "iris_code_shares_2=..." \
  -F "[email protected]" \
  -F "[email protected]"

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Response

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Success response

{
  "success": true,
  "credential": "<base64-credential>",
  "message": "Credential refreshed successfully"
}

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Error responses

StatusErrorDescription
400INVALID_SUBsub is missing or invalid.
400SUB_MISMATCHsub does not match the one used in previous refreshes.
404NO_SIGNUP_RECORDNo enrollment record found. User must re-enroll at an Orb.
429RATE_LIMIT_EXCEEDEDRefresh rate limit exceeded for the current window.
503-Credential refresh is disabled.
If PCP validation fails, the endpoint returns an error status with PCP_VALIDATION_FAILED.

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Credential object format

The credential response field is a base64-encoded JSON representation of the World ID Credential object defined in world-id-protocol/crates/primitives/src/credential.rs.

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Example (decoded)

{
  "id": 123456789,
  "version": "V1",
  "issuer_schema_id": 42,
  "sub": "<field-element-hex>",
  "genesis_issued_at": 1733241600,
  "expires_at": 1764777600,
  "claims": ["<field-element-hex>", "<field-element-hex>", "<field-element-hex>"],
  "associated_data_hash": "<field-element-hex>",
  "signature": "<signature-hex>",
  "issuer": {
    "pk": ["<x-decimal>", "<y-decimal>"]
  }
}

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Field definitions

FieldTypeDescription
iduint64Issuer-scoped reference identifier for the credential.
versionstringCredential version. Current value is V1.
issuer_schema_iduint64Identifier for the (issuer, schema) pair registered in CredentialSchemaIssuerRegistry.
subFieldElementBlinded subject identifier derived from the World ID leaf index and an issuer-specific blinding factor.
genesis_issued_atuint64Unix timestamp (seconds) of the first issuance of this credential.
expires_atuint64Unix timestamp (seconds) for expiration.
claimsFieldElement[]Up to 16 claim commitments. Unused indices are the zero field element.
associated_data_hashFieldElementPoseidon2 hash of issuer-defined associated data. The associated data itself is not included.
signaturestring64-byte compressed EdDSA signature over the credential hash, hex-encoded (128 hex chars, no 0x).
issuerEdDSAPublicKeyIssuer public key that signed the credential.

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Field representations

  • FieldElement values (sub, claims, associated_data_hash) are hex strings with a 0x prefix and 64 hex characters.
  • Issuer public key (issuer.pk) is serialized as [x, y] decimal strings for BabyJubJub affine coordinates.
  • Signature is hex-encoded compressed bytes (no 0x prefix).

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PoH credential semantics

  • The user first obtains an Orb credential (currently a PCP in v2.3 format).
  • claim[0] is a commitment to the Orb credential, currently H(hashes.json).
  • When refreshing without a PCP, claims[0] is derived from issuer-defined refresh data (a hash of idCommitment, sub, and a timestamp).
  • The PoH credential has no associated data, so associated_data_hash is the zero field element.
  • The PoH credential subject is blinded and differs from the Orb credential subject.
  • The issuer may require a proof for the requested sub to prevent bricking an identity.
These details are issuer-specific and may evolve as the protocol migrates to the World ID 4.0 credential format.

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References