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Documentation Index

Fetch the complete documentation index at: https://docs.nevermined.app/llms.txt

Use this file to discover all available pages before exploring further.

With the Payments Library it’s easy for users and AI agents to buy Payment Plans. The user only needs to hold sufficient balance in the plan currency (set on plan creation). With Nevermined, Plan creators can set payments currency to any valid ERC-20 or native token. Payment Plans can also be purchased in fiat (via Stripe or Braintree). The fiat checkout flow requires a credit card and is fully integrated into the Nevermined Web App. The active payment provider is selected per plan via the seller’s fiatPaymentProvider metadata at registration time. Nevermined likes to recommend stablecoin payments — that way the payment and fetching of credits associated with the Payment Plan can be done in a single step.

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Buying a Plan

// Here we are ordering the plan created in the previous steps
const orderResult = await payments.plans.orderPlan(planId)
// OUTPUT: orderResult:
// {
//   txHash: '0x5b95ebaec594b6d87e688faddf85eec3d708e6a06e61864699e5a366af1343f6',
//   success: true
// }

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Buying Plans with Fiat (Stripe or Braintree)

When the Payment Plan requires a payment in fiat, the payment is finalised in the Nevermined App. The app handles the checkout flow for the seller’s chosen provider (Stripe Checkout or Braintree Drop-in) and returns the user to the application that initiated the purchase flow. The SDK exposes a programmatic order method (orderFiatPlan) for Stripe-priced plans, which redirects the buyer to a Stripe Checkout session. Braintree-priced plans are checked out exclusively through the Nevermined App’s Drop-in flow — there is no SDK-level order method for Braintree today; link buyers to the plan’s purchase page on nevermined.app instead. 
// Get fiat payment configuration
const fiatConfig = await payments.plans.getFiatPriceConfig(planId)

// Order plan with fiat payment
const { sessionId, url } = await payments.plans.orderFiatPlan(planId)

// Redirect user to Stripe checkout
window.location.href = url

// After successful payment, user will be redirected back with the plan active

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Checking the Credit Balance of a Payment Plan

After a user purchases a plan, they can check their balance for that plan. The balance represents the number of credits the user has available to use within the plan.
Time-based plans provide a balance of 1 credit for subscribers. When the plan expires, this balance will be zero.
const balanceResult = await payments.plans.getPlanBalance(planId)
// OUTPUT: balanceResult:
// {
//   planId: '84262690312400469275420649384078993542777341811308941725027729655403981619104',
//   planType: 'credits',
//   holderAddress: '0x8924803472bb453b7c27a3C982A08f7515D7aA72',
//   creditsContract: '0x17FaFabF74312EdaBEB1DB9f0CaAccd44aAFDE39',
//   balance: '100',
//   isSubscriber: true
// }

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Understanding Plan Types and Balances

Credits-Based Plans

Users receive a specific number of credits upon purchase. Each API call consumes credits based on your pricing configuration.

Time-Based Plans

Users receive 1 credit that grants unlimited access for the specified duration. Balance becomes 0 when expired.

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Payment Flow Examples

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Complete Purchase Flow

1

Discover Plans

Users browse available payment plans and select one that fits their needs
2

Initiate Purchase

Call payments.plans.orderPlan() or payments.plans.orderFiatPlan() depending on payment method
3

Complete Payment

For crypto: transaction is processed on-chain and happens in one transaction. For fiat: user completes Stripe checkout, and the credits will be distributed automatically after the payment.
4

Verify Purchase

Check balance to confirm the plan was successfully purchased and get the balance. Call payments.plans.getPlanBalance().
5

Access Services

Use the plan to access AI agents and services. Call payments.x402.getX402AccessToken().

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Error Handling

try {
  const orderResult = await payments.plans.orderPlan(planId)
  
  if (orderResult.success) {
    console.log('Plan purchased successfully!')
    console.log('Transaction hash:', orderResult.txHash)
    
    // Check balance to confirm
    const balance = await payments.plans.getPlanBalance(planId)
    console.log('Available credits:', balance.balance)
  }
} catch (error) {
  console.error('Purchase failed:', error.message)
}

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Best Practices for Plan Purchasing

  • Always show clear pricing and what users get for their purchase
  • Create different plans for crypto and fiat payments if you want to support both
  • Show plan benefits and limitations clearly
  • Handle network failures gracefully with retry mechanisms
  • Provide clear error messages for common issues
  • Allow users to check their balance before making additional purchases
  • Implement transaction status checking for pending purchases
  • Never store private keys or sensitive wallet information
  • Validate plan purchases on the backend before granting access
  • Implement rate limiting to prevent abuse
  • Log purchase events for audit trails

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Next Steps

After users purchase plans, they can:

Query AI Agents

Learn how to access AI services with purchased plans

Handle Requests

Learn how to process requests and manage responses