When to Use Fiat Payments
Enterprise Adoption
Organizations that already pay for SaaS with corporate cards can onboard without touching crypto.
Mainstream Users
No wallet setup, no token bridging. Users pay with the card in their pocket.
Regulatory Compliance
Fiat-denominated billing simplifies accounting, invoicing, and compliance for businesses.
Instant Onboarding
Users go from discovery to first API call in seconds. No wallet funding step required.
Fiat Payment Scenarios
Nevermined supports fiat payments in two scenarios:- Human-to-Agent: A user visits the Nevermined App checkout page and purchases a plan with their credit card. This is the simplest flow for onboarding new customers.
- Agent-to-Agent: An agent owner enrolls a credit card and delegates payment permissions to an agent. The agent can then make autonomous payments on behalf of the owner, charging the delegated card per request.
Pay-per-request or a bundle of credits
Nevermined offers two distinct fiat payment flows depending on whether you want upfront plan purchases or per-request charging.Plan Purchase
One-time or recurring payment via Stripe Checkout. The user buys a plan, a webhook confirms the payment, and credits are minted on-chain. Best for human users who want a familiar checkout experience.
Card Delegation (x402)
Per-request charging via the x402 protocol. The user delegates their card with spending limits, and the agent charges it off-session for each request. Best for automated workflows and agent-to-agent payments.
Human-to-Agent Purchase Flow
The simplest way to accept fiat. Users complete a standard Stripe Checkout session, and Nevermined handles the rest.Select a plan
The user browses available plans in the Nevermined App or your custom UI and selects one priced in fiat.
Redirect to Stripe Checkout
Nevermined creates a Stripe Checkout session and redirects the user to complete payment with their card.
Payment completes
Stripe processes the charge. For recurring plans, Stripe manages subsequent billing automatically.
Webhook confirms payment
Nevermined receives a webhook from Stripe confirming the successful payment.
Agent-to-Agent Purchase Flow
Fully autonomous agent-to-agent payments in fiat are enabled through card delegation. This allows an agent to charge a user’s card on-demand, without the user needing to pre-purchase credits. Instead of buying credits upfront, the user authorizes Nevermined to charge their card within defined limits.Card Enrollment
The user enrolls a Card as a payment method. The card is registered through VGS (Very Good Security) to ensure PCI compliance, and a token is created that represents the card without exposing sensitive data.
Authorize delegation
The user authorizes a card delegation through the Nevermined App, setting spending limits (max total spend, max transactions, expiration date).
Receive delegation token
The user receives a delegation token that encodes their card authorization and spending limits.
Per-request charging via x402
When the agent makes a request, it includes the delegation token using the
nvm:card-delegation x402 scheme. The facilitator charges the delegated card off-session for each request.Card delegation is what enables fiat-based agent-to-agent payments. An agent owner delegates their card, and the agent can autonomously pay for services from other agents — all settled in fiat.
Permission Model
Card delegations enforce strict spending limits to protect the cardholder. Each delegation has three controls:| Limit | Description |
|---|---|
spendingLimitCents | Maximum total amount (in cents) that can be charged across all transactions |
maxTransactions | Maximum number of individual charges allowed |
expiresAt | Expiration date after which the delegation becomes invalid |
| State | Meaning |
|---|---|
| Active | The delegation is valid and can be used for charges |
| Exhausted | The spending limit or transaction count has been reached |
| Expired | The expiration date has passed |
| Revoked | The cardholder manually revoked the delegation |
Security and PCI Compliance
Card data never reaches Nevermined servers. All sensitive card information is tokenized through VGS (Very Good Security), a PCI-compliant proxy, before it reaches the facilitator. Nevermined only stores Stripe tokens, never raw card numbers.Nevermined is PCI compliant (PCI SAQ D level). VGS tokenizes card data in transit, and Stripe manages secure storage and charging. Your users’ card data is protected by industry-standard security at every step.
Revenue Routing with Stripe Connect
When a user pays with a card, Nevermined routes the revenue to the builder’s connected Stripe account using Stripe Connect. Fees are deducted automatically before the payout reaches the builder. This means you receive funds directly in your Stripe account — no manual transfers or reconciliation needed.Fees and Settlement
| Item | Cost |
|---|---|
| Nevermined fee | 2% of the transaction amount |
| Stripe processing fee | $0.50 + 4% per transaction |
| Settlement | Via Stripe PaymentIntents to builder’s connected account |
Supported Plan Types
Credits-Based
Prepaid credits purchased via Stripe Checkout. Credits are minted once payment confirms.
Time-Based
Subscription access for a set duration. Stripe handles recurring billing automatically.
Pay-As-You-Go
Per-request charging via card delegation. No upfront purchase needed.
Recurring
Automatic rebilling at the end of each period. Stripe manages the billing cycle.
Next Steps
Stablecoin Payments
Accept crypto payments with the lowest fees and on-chain transparency
x402 Card Delegation Spec
Full technical specification for the card delegation extension
Payment Models
Configure credits, time-based, dynamic, and hybrid plans
Manage Plans
Create and manage payment plans in the Nevermined App