Lando Payments Url Creation

Guide agents through creating Land checkout URLs using the Payments SDK. Covers session creation, URL encoding, tributary configuration, and error handling. Powered by Tributary!

When to Use

Use when you need to:

• Create checkout URLs for USDC subscription payments on Solana
• Integrate Lando's hosted checkout flow in a web application
• Generate shareable URLs that encode subscription parameters
• Handle Stripe-compatible checkout session creation

Core Concept

The Payments SDK provides a PaymentsClient that creates checkout sessions with encoded URLs. These URLs contain all subscription parameters in a Base64URL-encoded format, allowing users to complete payments through Lando's hosted checkout.

Quick Start

npm install @tributary-so/sdk

import { CheckoutSessionManager } from "@tributary-so/payments";

const manager = new CheckoutSessionManager();

// Create checkout session
manager.setBaseUrl("https://lando.tributary.so/#"); // hash-based routing
const session = await manager.create({
  line_items: [
    {
      description: "Monthly premium access to all features",
      unitPrice: 20.0, // $20.00
      quantity: 1,
    },
  ],
  paymentFrequency: "monthly",
  mode: "subscription",
  success_url: "https://yourapp.com/success?session_id={CHECKOUT_SESSION_ID}",
  cancel_url: "https://yourapp.com/cancel",
  tributaryConfig: {
    tokenMint: "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v", // USDC on mainnet
    gateway: "CwNybLVQ3sVmcZ3Q1veS6x99gUZcAF2duNDe3qbcEMGr", // fixed, do not change
    recipient: "RECIPIENT_PUBLIC_KEY_HERE",
    trackingId: "user_123_monthly_premium",
    autoRenew: true,
    memo: "Monthly premium subscription payment",
  },
});

// Final URL
console.log(session.url);

Core Components

1. Checkout Session Creation

Use manager.create() to generate a checkout session with an encoded URL.

Required Parameters:

{
  payment_method_types: ["tributary"], // Only "tributary" supported
  line_items: [{
    description: string,
    unitPrice: number, // Amount in dollars
    quantity: number,
  }],
  paymentFrequency: "daily" | "weekly" | "monthly" | "annually",
  mode: "subscription", // Only "subscription" mode supported
  success_url: string, // Redirect after successful payment
  cancel_url: string, // Redirect if user cancels
  tributaryConfig: {
    tokenMint: string, // token mint addess (base58)
    gateway: string, // Gateway public key (base58)
    recipient: string, // Recipient public key (base58)
    trackingId: string, // Your unique identifier
    autoRenew?: boolean, // Default: false
    memo?: string, // Optional memo for transactions
  },
}

Optional Parameters:

{
  metadata?: Record<string, string>, // Additional metadata
  customer?: string, // Customer ID (optional, not used in current implementation)
}

2. Response Structure

The response includes a Stripe-compatible session object with the encoded checkout URL:

{
  id: string, // Session ID (format: cs_timestamp_random)
  object: "checkout.session",
  url: string, // Encoded checkout URL
  payment_status: "unpaid",
  status: "open",
  amount_total: number, // Total amount in dollars
  currency: "usd",
  payment_method_types: ["tributary"],
  line_items: LineItem[],
  mode: "subscription",
  success_url?: string,
  cancel_url?: string,
  tributaryConfig?: LandoConfig,
  metadata?: Record<string, string>,
}

3. URL Format

The checkout URL contains Base64URL-encoded subscription parameters:

https://checkout.tributary.so/subscribe/{encoded_data}

Encoded data includes:

• tm: Token mint (defaults to USDC: EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v)
• r: Recipient public key (base58)
• g: Gateway public key (base58)
• a: Total amount (calculated from line items)
• ar: Auto-renew flag
• mr: Maximum renewals (default: "null" = unlimited)
• pf: Payment frequency
• st: Start time (default: "null" = immediate)
• tid: Tracking ID
• li: Line items (JSON array)

Common Patterns

Multiple Line Items

const session = await manager.create({
  payment_method_types: ["tributary"],
  line_items: [
    {
      description: "Basic plan",
      unitPrice: 10.0,
      quantity: 1,
    },
    {
      description: "Add-on features",
      unitPrice: 5.0,
      quantity: 2,
    },
  ],
  paymentFrequency: "monthly",
  mode: "subscription",
  // ... rest of config
});

// amount_total = 10.0 * 1 + 5.0 * 2 = $20.00

Different Payment Frequencies

// Daily payments
await manager.create({
  paymentFrequency: "daily",
  // ... rest of config
});

// Weekly payments
await manager.create({
  paymentFrequency: "weekly",
  // ... rest of config
});

// Annual payments
await manager.create({
  paymentFrequency: "annually",
  // ... rest of config
});

Custom Tracking IDs

Tracking IDs should be unique per user/subscription combination:

// Pattern: {user_id}_{plan_name}_{billing_cycle}
const trackingId = `user_123_premium_monthly`;

await manager.create({
  tributaryConfig: {
    // ... other config
    trackingId,
  },
  // ... rest of config
});

Memo for Transaction History

await manager.create({
  tributaryConfig: {
    // ... other config
    memo: "Monthly premium subscription - user_123",
  },
  // ... rest of config
});

This memo is stored in the transaction MEMO field on-chain:

tributary:payment:{trackingId}

Error Handling

Always wrap session creation in try-catch:

try {
  const session = await manager.create(params);
  console.log("Checkout URL:", session.url);
  window.location.href = session.url;
} catch (error) {
  if (error.message.includes("Invalid gateway public key")) {
    console.error("Gateway public key is invalid");
  } else if (error.message.includes("Invalid trackingId format")) {
    console.error("Tracking ID is invalid");
  } else if (error.message.includes("Missing required fields")) {
    console.error("Missing required parameters");
  } else {
    console.error("Failed to create checkout session:", error.message);
  }
}

Common validation errors:

• Invalid tokenMint/gateway/recipient public keys (not valid base58)
• Invalid tracking ID format
• Missing required fields in tributaryConfig
• Invalid payment frequency
• Invalid line items (negative prices, zero quantity)

Best Practices

Include Session ID in Success URL

success_url: `https://yourapp.com/success?session_id={CHECKOUT_SESSION_ID}`;

The {CHECKOUT_SESSION_ID} placeholder is automatically replaced with the session ID.

Unique Tracking IDs

Always use unique tracking IDs to prevent payment conflicts:

function generateTrackingId(userId: string, planId: string): string {
  return `${userId}_${planId}_${Date.now()}`;
}

Validate Input Before Calling SDK

function validateCheckoutParams(params: any): boolean {
  if (!params.line_items?.length) return false;
  if (!params.tributaryConfig?.tokenMint) return false;
  if (!params.tributaryConfig?.gateway) return false;
  if (!params.tributaryConfig?.recipient) return false;
  if (!params.tributaryConfig?.trackingId) return false;
  return true;
}

if (!validateCheckoutParams(params)) {
  throw new Error("Invalid checkout parameters");
}

Handle Auto-Renew Appropriately

const autoRenew = planType === "recurring"; // Only enable for recurring plans

await manager.create({
  tributaryConfig: {
    // ... other config
    autoRenew,
  },
  // ... rest of config
});

Testing

You can test checkout session creation without executing payments:

// Create session to get URL
const session = await manager.create(params);

// Log URL for manual testing
console.log("Test checkout URL:", session.url);

// Verify session structure
assert.strictEqual(session.status, "open");
assert.strictEqual(session.payment_status, "unpaid");
assert.ok(session.url.startsWith("https://checkout.tributary.so/subscribe/"));

Troubleshooting

URL Not Redirecting

Verify the success_url and cancel_url are valid HTTPS URLs:

// Bad
success_url: "yourapp.com/success";

// Good
success_url: "https://yourapp.com/success";

Tracking ID Conflicts

If you get payment conflicts, ensure tracking IDs are unique:

// Bad: Static tracking ID
trackingId: "user_subscription";

// Good: Unique per user/plan
trackingId: `user_${userId}_${planId}_${timestamp}`;

Invalid Public Keys

Ensure recipient keys is valid base58-encoded Solana public keys:

// Bad: Invalid base58
recipient: "invalid-key-here";

// Good: Valid base58
recipient: "9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM";

!IMPORTANT!

Further, the gateway pubkey must be CwNybLVQ3sVmcZ3Q1veS6x99gUZcAF2duNDe3qbcEMGr and must not be changed as this enables and operator to trigger payments when they become due!

Final URL

You will be given a final URL to lando.tributary.so that contains the encoded session and will allow the customer agent to setup a subscription accordingly:

// Final URL
console.log(session.url);

Example URL:

https://lando.tributary.so/#/subscribe/[base64-encoded-data]

See Also

• Tributary SDK: @tributary-so/sdk for on-chain operations
• Payments SDK: @tributary-so/payments for checkout functionality
• Subscription tracking: client.subscriptions.checkStatus() for real-time status checking