Circle’s Discovery API lets AI agents find and pay for services using USDC

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.

The stack is designed to be chain- and protocol-agnostic, with initial support spanning Arbitrum, Base, and Ethereum.

Why this matters for USDC and stablecoin competition

The compliance angle is worth lingering on. Every service in the Agent Marketplace undergoes screening for sanctions compliance and operational health before it’s discoverable through the API.

For the broader stablecoin market, Circle’s agent-focused strategy raises an interesting competitive question. Tether dominates in trading volume and overall circulation, but it hasn’t made comparable moves toward machine-to-machine infrastructure.

By launching across Arbitrum, Base, and Ethereum simultaneously, Circle is hedging against blockchain platform risk while maximizing the addressable developer population. Developers building on any of those chains can integrate the Discovery API without migrating their existing stack.

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