Buy Now, Pay Later for Crypto: How to Unlock High-Ticket Sales Without Credit Cards

The $500 Problem

You're selling a high-ticket item: a GPU ( $500), an online course ($ 300), a productivity tool ($200). Your conversion rate is decent—until customers see the price.

Then you watch them:

Add to cart
See total: $500
Abandon checkout

You know what they're thinking: "I want this, but I don't have $500 right now."

In traditional e-commerce, you'd offer Klarna, Affirm, or Afterpay. Customer pays $125/month for 4 months. You get paid upfront (minus ~6% fees). Everyone's happy.

But you're in crypto. And BNPL (Buy Now, Pay Later) for crypto... doesn't exist.

Until now.

Why BNPL Doesn't Exist in Crypto

Traditional BNPL works because:

They pull money from credit cards automatically
Credit bureaus provide risk scores
Debt collection agencies exist

Crypto has none of this:

❌ No automatic payments (wallets need to sign each transaction)
❌ No credit scores (wallets are pseudonymous)
❌ No debt collection (transactions are final)

So everyone assumed BNPL in crypto was impossible.

But what if we rethink the model?

The Crypto BNPL Model

Instead of trying to recreate credit card BNPL, we build something that actually works with crypto's properties:

Traditional BNPL (Affirm/Klarna):

Customer gets product immediately
BNPL company pays merchant upfront
BNPL company collects from customer monthly (with credit card)
BNPL company takes the risk

Problem: Requires credit infrastructure crypto doesn't have.

Crypto Installment Plans:

Customer pays first installment
Customer gets product after first payment
Customer pays remaining installments manually (with reminders)
Late fees for missed payments
Grace periods for forgiveness

Key insight: Treat it like recurring billing, not debt collection. Trust + incentives instead of credit checks + collection agencies.

Who This Works For

BNPL makes sense when:

✅ High-ticket items ($200+)
✅ Digital products (courses, tools, subscriptions)
✅ Physical goods (hardware, equipment)
✅ Predictable customers (existing users, verified accounts)
✅ Products with value AFTER first payment (courses you can access immediately)

❌ Low-ticket items (<$50) - not worth the complexity
❌ Anonymous buyers - too much risk
❌ One-time impulse purchases - standard checkout is fine

Building It: Step-by-Step

Let's build an installment plan system for a $500 GPU purchase.

Step 1: Install the SDK

npm install @zendfi/sdk

Step 2: Create an Installment Plan

import { zendfi } from '@zendfi/sdk';
 
// Customer wants to buy a $500 GPU in 4 installments
const plan = await zendfi.createInstallmentPlan({
  customer_wallet: 'CUSTOMER_SOLANA_WALLET',
  customer_email: 'customer@example.com',
  total_amount: 500,
  installment_count: 4,
  first_payment_date: new Date().toISOString(), // Pay first installment now
  payment_frequency_days: 30, // Monthly payments
  description: 'NVIDIA RTX 4090 GPU',
  late_fee_amount: 10, // $10 late fee if payment is late
  grace_period_days: 3, // 3-day grace period before late fee
  metadata: {
    product_id: 'gpu-rtx-4090',
    sku: 'GPU-4090-001',
  },
});
 
console.log(`Plan created: ${plan.plan_id}`);
console.log(`First payment: $${500 / 4} due now`);
console.log(`Remaining: 3 payments of $${500 / 4} every 30 days`);

What just happened:

Customer pays $125 today (first installment)
Gets access to product immediately
Owes 3 more payments of $125 each (day 30, 60, 90)
If payment is >3 days late, $10 late fee applies

Step 3: Check Payment Schedule

// Get the plan details
const planDetails = await zendfi.getInstallmentPlan(plan.plan_id);
 
console.log(`Payment schedule:`);
planDetails.payment_schedule?.forEach((installment) => {
  console.log(`
    Installment ${installment.installment_number}:
    Amount: $${installment.amount}
    Due: ${installment.due_date}
    Status: ${installment.status}
    ${installment.paid_at ? `Paid: ${installment.paid_at}` : ''}
  `);
});
 
// Output:
// Installment 1: $125 - Due: 2025-12-31 - Status: paid - Paid: 2025-12-31
// Installment 2: $125 - Due: 2026-01-30 - Status: pending
// Installment 3: $125 - Due: 2026-03-01 - Status: pending
// Installment 4: $125 - Due: 2026-03-31 - Status: pending

Step 4: Handle Webhook Notifications

Set up webhooks to track when payments are due, paid, or late:

// app/api/webhooks/zendfi/route.ts
import { verifyNextWebhook } from '@zendfi/sdk/webhooks';
 
export async function POST(request: Request) {
  const webhook = await verifyNextWebhook(request);
  
  if (!webhook) {
    return new Response('Invalid signature', { status: 401 });
  }
  
  switch (webhook.event) {
    case 'installment.due':
      // Payment is due in 3 days - send reminder
      const dueInstallment = webhook.data;
      await sendPaymentReminder({
        email: dueInstallment.customer_email,
        amount: dueInstallment.amount,
        due_date: dueInstallment.due_date,
        plan_id: dueInstallment.plan_id,
      });
      break;
      
    case 'installment.paid':
      // Payment received - thank customer
      const paidInstallment = webhook.data;
      await sendThankYouEmail({
        email: paidInstallment.customer_email,
        installment_number: paidInstallment.installment_number,
        remaining_payments: paidInstallment.remaining_count,
      });
      
      // Check if plan is complete
      if (paidInstallment.remaining_count === 0) {
        await markOrderAsFullyPaid(paidInstallment.plan_id);
      }
      break;
      
    case 'installment.late':
      // Payment is late - apply late fee and send warning
      const lateInstallment = webhook.data;
      await sendLatePaymentWarning({
        email: lateInstallment.customer_email,
        amount: lateInstallment.amount,
        late_fee: lateInstallment.late_fee,
        grace_period_end: lateInstallment.grace_period_end,
      });
      break;
  }
  
  return new Response('OK');
}

Webhook events:

installment.due - Payment due in 3 days (reminder)
installment.paid - Payment received successfully
installment.late - Payment is past due date + grace period

Step 5: Customer Payment Flow

On the customer dashboard, show remaining payments:

// app/dashboard/installments/page.tsx
'use client';
 
import { useEffect, useState } from 'react';
 
export default function InstallmentsPage() {
  const [plans, setPlans] = useState([]);
  
  useEffect(() => {
    // Fetch customer's installment plans
    fetch('/api/customer/installments')
      .then(r => r.json())
      .then(data => setPlans(data));
  }, []);
  
  const payInstallment = async (planId, installmentNumber) => {
    // Create payment for this specific installment
    const response = await fetch('/api/installments/pay', {
      method: 'POST',
      body: JSON.stringify({ plan_id: planId, installment_number: installmentNumber }),
    });
    
    const { payment_url } = await response.json();
    
    // Redirect to payment
    window.location.href = payment_url;
  };
  
  return (
    <div className="max-w-4xl mx-auto p-8">
      <h1 className="text-3xl font-bold mb-8">Your Installment Plans</h1>
      
      {plans.map(plan => (
        <div key={plan.plan_id} className="border rounded-lg p-6 mb-6">
          <h2 className="text-xl font-semibold">{plan.description}</h2>
          <p className="text-gray-600">Total: ${plan.total_amount}</p>
          <p className="text-gray-600">Paid: {plan.paid_count}/{plan.installment_count} installments</p>
          
          <div className="mt-4 space-y-2">
            {plan.payment_schedule.map(installment => (
              <div key={installment.installment_number} className="flex items-center justify-between border-b pb-2">
                <div>
                  <p className="font-medium">Installment {installment.installment_number}</p>
                  <p className="text-sm text-gray-600">Due: {new Date(installment.due_date).toLocaleDateString()}</p>
                </div>
                
                <div className="flex items-center gap-4">
                  <span className="font-bold">${installment.amount}</span>
                  
                  {installment.status === 'paid' ? (
                    <span className="text-green-600">✓ Paid</span>
                  ) : installment.status === 'pending' ? (
                    <button
                      onClick={() => payInstallment(plan.plan_id, installment.installment_number)}
                      className="bg-blue-600 text-white px-4 py-2 rounded"
                    >
                      Pay Now
                    </button>
                  ) : (
                    <span className="text-red-600">⚠ Late</span>
                  )}
                </div>
              </div>
            ))}
          </div>
          
          {plan.status === 'active' && (
            <p className="mt-4 text-sm text-gray-600">
              Next payment due: {new Date(plan.payment_schedule.find(i => i.status === 'pending')?.due_date).toLocaleDateString()}
            </p>
          )}
        </div>
      ))}
    </div>
  );
}

Real-World Example: Online Course Purchase

Let's walk through a complete flow for a $300 online course:

Backend: Create Installment Plan

// app/api/courses/[id]/installment/route.ts
import { zendfi } from '@zendfi/sdk';
 
export async function POST(request: Request) {
  const { courseId, installmentCount } = await request.json();
  const user = await getAuthenticatedUser(request);
  
  // Get course details
  const course = await db.courses.findOne({ id: courseId });
  
  // Create installment plan
  const plan = await zendfi.createInstallmentPlan({
    customer_wallet: user.wallet_address,
    customer_email: user.email,
    total_amount: course.price, // $300
    installment_count: installmentCount, // 3 installments
    first_payment_date: new Date().toISOString(),
    payment_frequency_days: 30,
    description: `${course.title} - Installment Plan`,
    late_fee_amount: 15, // $15 late fee
    grace_period_days: 5, // 5-day grace period
    metadata: {
      course_id: courseId,
      user_id: user.id,
    },
  });
  
  // Grant immediate access (after first payment)
  await db.enrollments.create({
    user_id: user.id,
    course_id: courseId,
    plan_id: plan.plan_id,
    status: 'active',
  });
  
  // Send confirmation email
  await sendEmail({
    to: user.email,
    subject: `Enrolled in ${course.title}!`,
    body: `
      You're enrolled! Here's your payment plan:
      - First payment: $${course.price / installmentCount} (paid today)
      - Remaining: ${installmentCount - 1} payments of $${course.price / installmentCount}
      - Schedule: Every 30 days
      
      Access your course: https://example.com/courses/${courseId}
    `,
  });
  
  return Response.json({
    plan_id: plan.plan_id,
    access_granted: true,
    next_payment_date: new Date(Date.now() + 30 * 24 * 60 * 60 * 1000).toISOString(),
  });
}

Email Reminders (Automated)

// Cron job (runs daily)
import { zendfi } from '@zendfi/sdk';
 
async function sendPaymentReminders() {
  // Get all active installment plans
  const plans = await zendfi.listInstallmentPlans({ status: 'active' });
  
  for (const plan of plans) {
    const nextInstallment = plan.payment_schedule?.find(i => i.status === 'pending');
    
    if (!nextInstallment) continue;
    
    const daysUntilDue = Math.floor(
      (new Date(nextInstallment.due_date).getTime() - Date.now()) / (1000 * 60 * 60 * 24)
    );
    
    // Send reminder 3 days before due
    if (daysUntilDue === 3) {
      await sendEmail({
        to: plan.customer_email,
        subject: 'Payment reminder: Due in 3 days',
        body: `
          Hi! Your next installment payment is due in 3 days.
          
          Amount: $${nextInstallment.amount}
          Due date: ${new Date(nextInstallment.due_date).toLocaleDateString()}
          
          Pay now: https://example.com/installments/${plan.plan_id}/pay
        `,
      });
    }
    
    // Send urgent reminder on due date
    if (daysUntilDue === 0) {
      await sendEmail({
        to: plan.customer_email,
        subject: '⚠️ Payment due today',
        body: `
          Your installment payment of $${nextInstallment.amount} is due today.
          
          Pay now to avoid late fees: https://example.com/installments/${plan.plan_id}/pay
          
          (Grace period: ${plan.grace_period_days} days)
        `,
      });
    }
  }
}
 
// Run daily at 9am
setInterval(sendPaymentReminders, 24 * 60 * 60 * 1000);

The Economics: Does This Actually Work?

Let's compare standard checkout vs installment plans:

Scenario: $300 Online Course

Standard Checkout:

Conversion rate: 5%
1,000 visitors → 50 sales
Revenue: 50 × $300 = **$ 15,000**

Installment Plans (3 payments):

Conversion rate: 12% (higher, lower barrier)
1,000 visitors → 120 sales
Revenue: 120 × $300 = **$ 36,000**
Late fees collected: ~5% miss payments = 6 customers × $15 = **$ 90**
Defaults: ~2% never complete = 2 × $300 = **-$ 600** (lost revenue)

Net installment revenue: $35,490

Increase: +$20,490 (+136%)

The math works because:

More people can afford $100/month than$ 300 upfront
Late fees cover admin overhead
Default rate is low (2-5%) when you grant access immediately

Handling Defaults

What if someone stops paying after installment 2 of 4?

Option 1: Revoke Access (Harsh)

case 'installment.late':
  const lateInstallment = webhook.data;
  
  // If more than 10 days late, revoke access
  if (lateInstallment.days_late > 10) {
    await db.enrollments.update({
      where: { plan_id: lateInstallment.plan_id },
      data: { status: 'suspended' },
    });
    
    await sendEmail({
      to: lateInstallment.customer_email,
      subject: 'Access suspended',
      body: 'Your access has been suspended due to late payment. Pay now to restore access.',
    });
  }
  break;

Option 2: Reduce Access (Lenient)

case 'installment.late':
  // Instead of full suspension, limit features
  await db.enrollments.update({
    where: { plan_id: webhook.data.plan_id },
    data: { access_level: 'limited' }, // Can view already-started modules, but not new ones
  });
  
  await sendEmail({
    to: webhook.data.customer_email,
    subject: 'Payment overdue - limited access',
    body: 'Your access is now limited. Pay to restore full access.',
  });
  break;

Option 3: Write It Off (Generous)

// If customer paid ≥50% of total, forgive remaining
if (plan.paid_count >= plan.installment_count / 2) {
  await zendfi.cancelInstallmentPlan(plan.plan_id, {
    reason: 'forgiven',
  });
  
  await sendEmail({
    to: plan.customer_email,
    subject: 'Your remaining balance has been forgiven',
    body: 'Thank you for being a customer. Your remaining payments have been waived.',
  });
}

Most successful implementations use Option 2 (reduce access) because:

Customer has already received value (harder to justify full revoke)
Lenient policy = better reputation
Defaulters might return and pay later

Advanced: Variable Installments

Not all installments need to be equal:

// Larger first payment, smaller later ones
const plan = await zendfi.createInstallmentPlan({
  customer_wallet: customerWallet,
  customer_email: 'customer@example.com',
  total_amount: 500,
  installment_count: 4,
  payment_frequency_days: 30,
  description: 'GPU Purchase',
  custom_schedule: [
    { installment_number: 1, amount: 200 }, // $200 upfront
    { installment_number: 2, amount: 100 }, // $100 month 1
    { installment_number: 3, amount: 100 }, // $100 month 2
    { installment_number: 4, amount: 100 }, // $100 month 3
  ],
});
 
// Customer pays $200 now, gets product
// Lower monthly payments increase likelihood of completion

Or graduated payments (smaller first, larger later):

custom_schedule: [
  { installment_number: 1, amount: 50 },   // Easier to start
  { installment_number: 2, amount: 100 },  // Ramp up
  { installment_number: 3, amount: 150 },  // Ramp up
  { installment_number: 4, amount: 200 },  // Final large payment
]

Common Objections

"Why would anyone use this over a credit card?"

No credit card - Many crypto users don't have/want credit cards
No credit check - Instantly approved, no FICO score needed
No interest - Unlike credit cards (20%+ APR), installment plans are 0% interest
Crypto-native - Some users prefer to pay in USDC

"What's your default rate?"

Industry averages for BNPL:

Traditional (Affirm): 2-5% default rate
Crypto installments: 5-10% (higher because no credit checks)

But you're not Affirm. You're not taking the full risk. Customer pays first installment upfront, so you're only exposed to remaining 75%.

"How do you prevent fraud?"

Require account history - Only offer installments to users with ≥30 days account age
Limit plan values - Cap at $500 per customer until they prove trustworthy
First payment upfront - Customer pays 25-50% before access
Progressive trust - Complete 1 plan successfully → eligible for larger plans

"What about chargebacks?"

Crypto transactions are final. No chargebacks. But you can:

Offer refunds voluntarily (good customer service)
Use dispute resolution systems
Build reputation systems (good buyers get better terms)

Production Checklist

Before launching installment plans:

✅ Financial Planning

Define default tolerance (how many defaults can you absorb?)
Set installment limits per customer ( $500?$ 1,000?)
Decide: equal installments or variable?
Calculate late fees (should cover admin costs)
Determine grace periods (3-7 days typical)

✅ Technical Setup

Implement installment plan creation
Set up webhook handlers (due, paid, late)
Build customer dashboard (show remaining payments)
Create email reminder system (automated)
Test full flow with devnet USDC

✅ Risk Management

Require account verification for large plans
Implement progressive trust system
Set up fraud detection (suspicious patterns)
Define revocation policy (when to suspend access)
Create dispute resolution process

✅ Customer Experience

Clear payment schedule on checkout
Email reminders (3 days before, day of, day after)
Easy one-click payment from reminders
Transparent about late fees and grace periods
Provide support for payment issues

Why This Changes High-Ticket Sales

Traditional crypto has one payment mode: pay full price upfront or don't buy.

This leaves huge money on the table:

$500 course? Most can't afford it upfront
$1,000 hardware? Too risky for one payment
$200/year subscription? Annual prepay is a barrier

Installment plans unlock these sales while maintaining instant settlement benefits of crypto.

You're not competing with Klarna. You're offering something better: 0% interest, crypto-native payment plans with instant access.

What's Next?

We're working on:

Auto-debit with session keys - Optional auto-pay for trusted customers
Dynamic payment dates - Align with customer's pay schedule
Split installments - Multiple recipients per installment
Subscription installments - Recurring payments with installment options
Risk scoring - AI-powered default prediction

Try It Yourself

Complete examples and starter templates:

Tutorials:

Code:

Dashboard:

Resources

SDK Documentation: docs.zendfi.tech
Installment Plans API: docs.zendfi.tech/installments
Webhook Reference: docs.zendfi.tech/webhooks
Risk Management: docs.zendfi.tech/risk

Questions? Find us on Twitter or Discord.

Building payment infrastructure for the future. Where crypto meets consumer financing.