Agentcard gives companies a way to let AI agents pay at ordinary online checkouts. It sells to teams building personal assistants and other agents that can already shop, then stop, because merchants still want a card and the founders have said online stores do not support protocols such as x402. The YC Summer 2026 startup just left agentcard.sh for agentcard.com. Co-founder Karen Serfaty announced the move with a short film featuring HubSpot co-founder Dharmesh Shah, who is also an investor. The company called the film a mostly accurate account of how they got the domain. The company tells most customers to start with Vault. A customer saves a card once in a PCI-compliant vault. The agent checks out with a placeholder, the customer approves with Face ID or a passkey, and the real card goes to the merchant, so rewards and bank disputes stay with the cardholder. It works with Visa, Mastercard, and Amex from any country, and it is free up to 5,000 users. Issuing covers the other case. A business verifies once, loads a balance, and its agents get one-time cards for a purchase or multi-use cards for a subscription, issued by Rain and settled in USDC on Base. Checkout connects through Kernel, Browserbase, Browser Use, Anchor, or a company's own browser, and a purchase endpoint can complete orders at merchants including Amazon, DoorDash, and airlines. Serfaty previously founded Atlas, an expense card for global teams that Remote acquired, and was later general manager of cards at Remote. Co-founder and CTO Felipe Abello was Rappi's first employee and a second-time YC founder (HelloGuru, W22). They are based in San Francisco, selling to companies whose agents need to buy on the card networks stores already accept.