Circle just made it easier for AI agents to shop around. The USDC issuer rolled out a Discovery API on July 31 as part of its broader Agent Stack platform, giving autonomous software a way to browse, filter, and evaluate services that accept USDC payments, all without a human logging in.
What the Discovery API actually does
The API works as a public endpoint, meaning AI agents can query it without user authentication. Most financial APIs require some form of login or credentialing before you can even browse what’s available.
The endpoint supports 14 query parameters for filtering results. Agents can search by category, blockchain, pricing, and other criteria to find services that match their specific needs. Every service listed in the marketplace has been pre-screened, which means agents aren’t just finding random endpoints. They’re discovering counterparties that have already passed compliance checks.
The Discovery API builds on Circle’s Agent Stack, which launched on May 11 alongside the company’s Q1 2026 earnings. That initial release included Agent Wallets for autonomous fund management, a Nanopayments system for small machine-to-machine transfers, and an Agent Marketplace where services could list themselves for discovery by other agents.
