2. Offchain Integration

import express from 'express';

const app = express();
app.use(express.json());

app.post('/api/compliance/check', async (req, res) => {
  const { userAddress } = req.body;

  const response = await fetch('https://api.predicate.io/v2/attestation', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'x-api-key': process.env.PREDICATE_API_KEY,
    },
    body: JSON.stringify({
      verification_hash: process.env.PREDICATE_VERIFICATION_HASH,
      from: userAddress,
      chain: 'ethereum',
    }),
  });

  const result = await response.json();

  if (!result.is_compliant) {
    return res.status(403).json({
      error: 'User not compliant',
      policy: result.policy_name,
      reason: result.reason, // may include code and message from the policy
    });
  }

  // User is compliant — proceed with your business logic
  res.json({ compliant: true });
});

{
  "policy_id": "policy_abc123",
  "policy_name": "Standard AML Policy",
  "verification_hash": "x-abc123def456",
  "is_compliant": true,
  "attestation": {
    "uuid": "550e8400-e29b-41d4-a716-446655440000",
    "expiration": 1696640400,
    "attester": "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266",
    "signature": "0x1b2c3d4e5f..."
  }
}

{
  "policy_id": "x-dev-trm-risk-abc123",
  "policy_name": "TRM Risk Score",
  "verification_hash": "x-abc123def456",
  "is_compliant": false,
  "attestation": {
    "uuid": "550e8400-e29b-41d4-a716-446655440000",
    "expiration": 0,
    "attester": "",
    "signature": ""
  },
  "reason": {
    "code": "trm_high_risk",
    "message": "TRM risk score for this wallet is 10 which exceeds the maximum allowed of 7"
  }
}