Add Chargeback Prevention to Your AI Infrastructure

Deprecated, and this guide has not been rewritten off it. @observer-protocol/sdk and the PyPI package observer-protocol were last released in April 2026, are unmaintained, and carry a deprecation notice on the registry itself. Everything below still installs and still runs. For verifying a credential use @observer-protocol/policy-engine instead; for the register/attest flows in Steps 2 and 3 there is no replacement package yet, which is why this page still names the old one. See the SDK page for what replaces which part.

TypeScript

npm install @observer-protocol/sdk

Python

pip install observer-protocol

Register your AI infrastructure service with a DID so agents can discover and verify you.

TypeScript

import { ObserverClient } from '@observer-protocol/sdk';

const client = new ObserverClient();

const service = await client.registerAgent({
  publicKey: 'your_ed25519_public_key_hex',
  agentName: 'Your AI Infra Service',
});

// Verify key ownership
const challenge = await client.requestChallenge(service.agentId);
// Sign challenge.nonce with your private key
await client.verifyAgent(service.agentId, signatureHex);

// Your service is now:
// - Discoverable via DID: did:web:observerprotocol.org:agents:{id}
// - Verifiable by any agent or counterparty
// - Ready to issue and verify delegation credentials

Python

from observer_protocol import ObserverClient

client = ObserverClient()
pub, priv = ObserverClient.generate_keypair()

service = client.register_agent(public_key=pub, agent_name="Your AI Infra Service")
challenge = client.request_challenge(service.agent_id)
sig = ObserverClient.sign_challenge(priv, challenge.nonce)
client.verify_agent(service.agent_id, sig)

When an agent pays for your service via x402, verify the payment and issue a credential.

TypeScript

// After receiving an x402 payment from an agent
const result = await client.verifyX402({
  agentId: 'd13cdfceaa8f895afe56dc902179d279',
  agentDid: 'did:web:observerprotocol.org:agents:d13cdf...',
  counterparty: 'did:web:your-service.com',
  amount: '100000', // 0.10 USDC in atomic units
  resourceUri: 'https://api.your-service.com/v1/inference',
  settlementTxHash: '0xd94a6d8bfa9c1634e19b59cac9503e732cb538772b96e02300702bc38fb39b94',
  paymentPayload: paymentResponseFromX402,
});

// result.verification.onchainVerified = true
// result.credential = W3C VC signed by OP
// result.eventId = audit trail reference

Python

result = client.verify_x402(
    agent_id="d13cdfceaa8f895afe56dc902179d279",
    agent_did="did:web:observerprotocol.org:agents:d13cdf...",
    counterparty="did:web:your-service.com",
    amount="100000",
    resource_uri="https://api.your-service.com/v1/inference",
    settlement_tx_hash="0xd94a6d8bfa9c...",
    payment_payload=payment_response,
)

assert result.verification.onchain_verified  # True

Verification requires only the authorization-proof JSON and the issuer's published public key. No API key, no token, no Observer Protocol API in the path. Note that resolve_did below fetches the issuer's DID document over ordinary HTTPS from the origin the credential names — supply the document yourself and it makes no network call at all.

from observer_protocol import verify_receipt, resolve_did

issuer_key = resolve_did(receipt_json['issuer']['id'])
result = verify_receipt(receipt_json, issuer_key)
assert result.valid  # cryptographic proof verified

Four lines, no API key, and nothing either OP or the counterparty can withhold to stop it verifying. Any third party can verify.