Pi Payments

Pi Payments

Implement Pioneer-to-App payments using the Pi SDK's three-phase flow. All financial transactions in Pi Apps must use Pi exclusively - no fiat or other crypto.

When to Use This Skill

• Implementing Pi payment flow
• Building server-side approve/complete endpoints
• Debugging payment failures or incomplete payments
• Understanding PaymentDTO structure

Three-Phase Payment Flow

Phase I:   Frontend creates payment -> SDK gets paymentId -> Backend approves
Phase II:  Pioneer confirms in Pi Wallet -> Blockchain processes transaction
Phase III: SDK gets txid -> Backend completes -> Payment dialog closes

Phase I - Creation & Server Approval

1. Frontend calls Pi.createPayment(paymentData, callbacks)
2. SDK opens Payment Flow UI (non-interactive until approved)
3. onReadyForServerApproval(paymentId) callback fires
4. Backend calls POST /v2/payments/{paymentId}/approve with Server API Key
5. Payment UI becomes interactive for Pioneer

Phase II - Pioneer Interaction & Blockchain

1. Pioneer confirms payment in Pi Wallet
2. Pioneer signs and submits transaction to blockchain
3. Blockchain processes and returns transaction info

Phase III - Server Completion

1. onReadyForServerCompletion(paymentId, txid) callback fires
2. Backend calls POST /v2/payments/{paymentId}/complete with { txid }
3. Payment dialog closes, app becomes visible again

Frontend Implementation

const paymentData = {
    amount: 3.14,                    // Pi amount (number)
    memo: "Purchase item #1234",      // Shown to Pioneer (string)
    metadata: { orderId: 1234 }       // Your custom data (object)
};

const paymentCallbacks = {
    onReadyForServerApproval: function(paymentId) {
        // Send paymentId to YOUR backend
        axios.post('/api/payments/approve', { paymentId });
    },
    onReadyForServerCompletion: function(paymentId, txid) {
        // Send paymentId + txid to YOUR backend
        axios.post('/api/payments/complete', { paymentId, txid });
    },
    onCancel: function(paymentId) {
        console.log('Payment cancelled:', paymentId);
    },
    onError: function(error, payment) {
        console.error('Payment error:', error, payment);
    }
};

Pi.createPayment(paymentData, paymentCallbacks);

Backend API Calls

Use the Server API Key (from Developer Portal) with Authorization: Key <key> header.

Approve Payment

const headers = { authorization: `Key ${SERVER_API_KEY}` };
await axios.post(
    `https://api.minepi.com/v2/payments/${paymentId}/approve`,
    null,
    { headers }
);

Complete Payment

const headers = { authorization: `Key ${SERVER_API_KEY}` };
await axios.post(
    `https://api.minepi.com/v2/payments/${paymentId}/complete`,
    { txid: transactionId },
    { headers }
);

Get Payment Details

const headers = { authorization: `Key ${SERVER_API_KEY}` };
const response = await axios.get(
    `https://api.minepi.com/v2/payments/${paymentId}`,
    { headers }
);

Handling Incomplete Payments

Always handle incomplete payments from previous sessions in the authenticate callback:

function onIncompletePaymentFound(payment) {
    // Send to backend to check status and complete or cancel
    axios.post('/api/payments/incomplete', { payment })
        .then(result => console.log('Resolved:', result))
        .catch(err => console.error('Failed to resolve:', err));
}

Pi.authenticate(scopes, onIncompletePaymentFound);

PaymentDTO Structure

{
    "identifier": "string (paymentId)",
    "Pioneer_uid": "string (app-specific user ID)",
    "amount": 3.14,
    "memo": "string (shown to Pioneer)",
    "metadata": { "orderId": 1234 },
    "to_address": "string (blockchain recipient wallet)",
    "created_at": "ISO 8601 timestamp",
    "status": {
        "developer_approved": true,
        "transaction_verified": true,
        "developer_completed": true,
        "canceled": false,
        "Pioneer_cancelled": false
    },
    "transaction": {
        "txid": "string (64 hex chars)",
        "verified": true,
        "_link": "string (blockchain explorer URL)"
    }
}

Critical Security Rule

Do NOT complete any payment in your app until /complete returns HTTP 200. Malicious users can manipulate SDK versions to simulate payments. Only mark transactions as complete after the server-side /complete call succeeds.

Troubleshooting

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