Cardano officially joined the x402 payment standard on September 21, enabling applications and autonomous AI agents to pay for online services directly in ADA. ADA rose about 4% over the past 24 hours to a four-month high, according to BeInCrypto data. Cardano Foundation engineers built the client, server and facilitator components after the specification merged into the official x402 repository around September 9, and the facilitator has already processed a transaction on Cardano’s pre-production testing network.