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This guide walks through the end-to-end integration of Newton Verifiable Credentials into your app. Before starting, read the overview to understand how Newton VC works.

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Prerequisites

RequirementDetails
Newton SDK@magicnewton/newton-protocol-sdk installed and configured
Newton API keyCreate one in the dashboard
Policy client contractMust inherit NewtonPolicyClient + EIP712 and be registered with PolicyClientRegistry
Identity domainA bytes32 string (keccak256 of your domain, e.g. keccak256(bytes("my.dev.domain.co")))
KYC vendorA third-party vendor to collect user identity data

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Step 1: Write and Deploy a Policy

Write a Rego policy that uses Newton identity built-in functions. For example, to enforce that a user is approved and at least 18 years old: 
package example

import future.keywords.if

authorized if {
    newton.identity.kyc.check_approved()
    newton.identity.kyc.age_gte(18)
    newton.identity.kyc.address_in_countries(["US","CA","DE"])
}
Set the policy params to include your identity domain, in addition to another other params that you may need: 
{
  "identity_domain": "0x<keccak256 of your domain string>"
}
The identity_domain value is the keccak256 hash of your domain string encoded as a bytes32 hex value. For example: keccak256(bytes("my.dev.domain.co")). This scopes the identity data to your application. An example value of this is 0x70013f8147873660b512807fffa46355f43463c571a0b05eea4ede282dfcf523
See the Identity Policy Reference for all available built-in functions.

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Step 2: Deploy a Policy Client Contract

Your policy client must inherit from both NewtonPolicyClient and EIP712. See the Reference for a complete sample contract. Key requirements:
  • Inherit NewtonPolicyClient and EIP712
  • Call _initNewtonPolicyClient(policyTaskManager, owner) in the constructor
  • Register the contract with the PolicyClientRegistry — see Smart Contract Integration

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Step 3: Collect KYC Data

Collect identity data from your users using a third-party KYC vendor. The structure of this data maps to the fields Newton’s identity policy engine reads (see IdentityData fields).

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Step 4: Register KYC Data

Once you have the KYC data, call registerUserData to register it with Newton, scoped to your identity domain: 
const walletClient = createWalletClient({ ... }).extend(
  newtonWalletClientActions({ apiKey: 'YOUR_API_KEY' })
)

await walletClient.registerUserData({
  userData: kycDataFromVendor,
  appIdentityDomain: '0x<keccak256 of your domain string>',
})
This opens the Newton identity popup, where Newton securely stores the KYC data associated with the user.

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Step 5: User Confirms KYC Data

The user sees a confirmation prompt in the Newton identity flow to verify the KYC data being registered. This is handled by the popup opened in Step 4. Call linkApp to link the user’s registered identity to your policy client contract: 
await walletClient.linkApp({
  appWalletAddress: userWalletAddress,
  appClientAddress: yourPolicyClientAddress,
  appIdentityDomain: '0x<keccak256 of your domain string>',
})
This triggers a prompt for the user to sign and confirm the link. The user completes the link confirmation in the Newton identity popup. Under the hood, this calls linkIdentityAsUser on the IdentityRegistry contract — a transaction signed by the user’s wallet. See SDK & Contract Reference for the full contract function signature.

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Step 8: Submit a Task

Submit a task with a signed intent from the user’s dapp wallet (the same wallet that confirmed the link in Step 7). The intent must be signed using the EIP712 domain of your policy client: 
await walletClient.submitEvaluationRequest({
  intent: signedIntent,
  policyId: yourPolicyId,
  intentSignature: intentSignature,
  // ...other task params
})
Newton evaluates the Rego policy, checks identity data, and returns an attestation if the policy passes.

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Unlinking

To remove a user’s identity link from your app, call unlinkApp: 
await walletClient.unlinkApp({
  appWalletAddress: userWalletAddress,
  appClientAddress: yourPolicyClientAddress,
  appIdentityDomain: '0x<keccak256 of your domain string>',
})

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Reference Pages

SDK & Contract Reference

Full SDK method signatures and contract functions

Identity Policy Reference

All Rego built-in functions for identity checks

Have questions?

Get in touch with someone from the Newton team to discuss your integration