Cardano has been added to the official x402 software kit, allowing developers to build applications and AI agents that pay for online services with ADA or tokens issued on the network. The HTTP-based standard turns a 402 Payment Required response into a per-request payment flow: a service returns pricing and payment instructions, the client signs a transaction, and access is provided after verification. Cardano Foundation engineers built client, server and facilitator software after a specification was accepted in June, with TypeScript support available initially and Python planned next. The facilitator has completed a real transaction on Cardano's pre-production network, but its documentation says it has not yet operated on mainnet. Coinbase created x402 in 2025 and later contributed it to a Linux Foundation-backed organization whose members include Visa, Mastercard, Stripe, Google and Amazon Web Services. Adoption has expanded across networks and services: XRP Ledger reported more than 1 million AI-related x402 payments by July and later exceeded 1.4 million agent transactions, while Coinbase said its developer platform processed more than 100 million x402 payments across Base and Solana in September.