July 2026
Launched the Agent Marketplace, a curated catalog of
x402-compatible services that accept
USDC. Every listing is sanctions-screened and health-checked, so agents find
services that are compliant and live.Two new integration paths:
- Buyers (AI agents) discover services through the public, keyless
Discovery API—
GET https://api.circle.com/v2/x402/discovery/resources—with 14 query parameters to filter by category, blockchain, price, and more. No API key or account required. - Sellers (API owners) list a service and get paid in USDC per call. See Become a seller for the nanopayments and vanilla x402 rails, or Get listed to submit a listing.
May 2026
Added documentation for Agent Nanopayments, which enables AI agents to make
sub-cent USDC payments to x402-compatible services using Circle CLI.
Documentation additions
The following Agent Nanopayments documentation was created:- Agent nanopayments
- Quickstart: Make a nanopayment
- Nanopayment operations
- How-to: Withdraw your balance
Documentation updates
The following how-tos moved from Agent Wallets into the new Agent Nanopayments section:Launched Agent Stack, a new product line for AI agents to manage wallets,
transact onchain, and pay for x402-compatible services using Circle CLI.
Documentation additions
The following Agent Stack and Circle CLI documentation was created:The following Agent Wallets documentation was created:- Agent wallets
- Quickstart: Create an agent wallet
- Agent wallet supported blockchains
- Agent wallet fees
- Wallet operations
- How-to: Authenticate an agent wallet
- How-to: Fund an agent wallet
- How-to: Transfer USDC
- How-to: Bridge USDC
- How-to: Swap tokens
- How-to: Deposit for nanopayments
- How-to: Pay for a service
- How-to: Execute a smart contract
- How-to: Sign a message
- How-to: Set spending policies