- The traditional web runs on cards. Amazon, Shopify stores, SaaS checkouts, and most traditional merchants rely on card payments. Users expect familiar properties like card rewards, refunds, and chargebacks.
- The agentic web runs on stablecoins. x402 and MPP-gated APIs, micropayments, and machine-to-machine settlement require stablecoins. Cards don’t work here since fees, chargebacks, and merchant account constraints make small or programmatic payments impractical.
Payment methods need limits
You cannot give an agent unrestricted access to money:- Credentials can be leaked
- Agents can overspend or behave unexpectedly
- Card agentic protocols. The user’s real card is stored in a PCI-compliant vault. Users create virtual cards for agents with limits (amount, merchant, duration), enforced at the network level via Visa VIC and Mastercard Agent Pay. Developers never handle sensitive information.
- Wallet non-custodial delegation. The user owns the wallet and grants the agent scoped permissions (spend limit, counterparties, time window). Developers and agents never take custody of funds.
User flows
Every payment method an agent uses is set up through a user flow — a hosted, customizable UI where the user explicitly delegates access. The flows below cover the end to end integration steps for both cards and wallets. One principle holds across all of them: the user stays in control. Every delegation is explicit, scoped, and revocable. Crossmint provides the UI components and signing flows. You wire them into your product.- Cards
- Stablecoin wallets
User enrolls the card for agentic use
This step links the card to the “agentic” card rails.
- Happens in a Crossmint component
- User verifies ownership (e.g. SMS or bank auth)
- A passkey is created for future approvals
A virtual card is created with limits
The developer requests a virtual card with limits (amount, merchant, expiration). A network modal (Visa/Mastercard) appears and the user confirms using their passkey.
How agents actually pay
Once setup is complete, agents can spend. The payment flow depends on where they are paying.| Flow | Payment method | How it works | Best for |
|---|---|---|---|
| x402 | Stablecoin | Agent calls an endpoint, receives 402 Payment Required, pays in stablecoin, retries | Pay-per-call APIs, micropayments |
| MPP | Stablecoin | Agent-to-agent and service-to-service payments over a payment protocol | Programmatic machine economies |
| Browser Checkout | Card | Agent drives a real browser and fills checkout forms using a virtual card | Any website that accepts cards |
| Fast Checkout | Card or stablecoin | A single API call replaces the entire checkout flow — no browser needed | Amazon, Shopify stores (US only) |
Choose Your Path
Cards quickstart
Build an agent paying with virtual cards.
Wallets quickstart
Build an agent paying with stablecoins.