The Cardano Foundation has integrated its blockchain into the x402 SDK, enabling applications and autonomous AI agents to pay for API calls directly via HTTP requests. This implementation, which was merged into the official x402 repository on September 9, 2026, eliminates the need for traditional accounts, API keys, or subscription management.
The protocol utilizes the HTTP 402 status code, which signifies that payment is required. When a client requests data, the server returns this status, prompting the client to submit a signed transaction on the Cardano blockchain. The system leverages Cardano’s eUTxO model to ensure that payment and verification occur within a single cryptographic step.
The integration supports the Cardano mainnet, as well as the preprod and preview testnets. Beyond the native ADA token, the framework facilitates payments using Cardano-native stablecoins, specifically USDM, DJED, and iUSD. This feature is designed to mitigate price volatility for automated services such as data retrieval or AI model inference.
Unlike previous third-party implementations, such as those by the Masumi Network, this integration is part of the canonical codebase overseen by the x402 Foundation under the Linux Foundation. Cardano Foundation engineers contributed the necessary client, server, and facilitator components, providing developers with standardized templates for implementation.
