Glossary

A cryptographic wallet controlled directly by an AI agent — allowing the software to autonomously hold, receive, and spend digital assets within strictly defined, human-set limits.

An open standard that lets autonomous AI agents built by different developers discover one another, delegate tasks, and collaborate as network peers — the coordination layer beneath autonomous commerce.

A model of digital trade where AI agents autonomously discover products, negotiate terms, and execute payments on behalf of human users or other machines — without human approval at each transaction step.

An open-source cryptographic authorization standard governed by the FIDO Alliance that gives AI agents a verifiable, tamper-evident proof of human consent before they autonomously execute financial transactions.

An enterprise-grade runtime feature built into Amazon Bedrock in partnership with Coinbase and Stripe that equips AI agents with embedded stablecoin wallets to autonomously discover and purchase paywalled digital resources.

An Ethereum Layer 2 network incubated by Coinbase, built on the OP Stack — a primary low-cost settlement chain for on-chain machine payments and USDC.

A full-stack infrastructure suite from Circle that equips autonomous AI agents with policy-controlled wallets, a service discovery marketplace, and a sub-cent nanopayment rail to transact across the internet using USDC.

An Ethereum standard that gives AI agents a verifiable on-chain identity — including a reputation registry and validation registry — so they can be trusted parties in machine-to-machine transactions.

A macroeconomic system in which autonomous AI agents and connected physical machines act as independent economic participants — holding capital, executing transactions, and generating value without human intervention at each step.

An open, HTTP-native payment standard co-authored by Stripe and Tempo Labs that enables autonomous AI agents to pay for digital resources using both stablecoins and traditional fiat rails within a single protocol.

A financial transaction worth a fraction of a cent — enabled by blockchain batching and off-chain settlement — that allows machines to pay for digital resources on a strict pay-per-use basis at machine speed.

A filtered measure of payment activity that removes bot-generated transactions, wash trading, and automated test traffic to estimate genuine machine-to-machine commerce. MachineEconomy.ai does not use a quality-adjusted figure in the MEI — it publishes gross on-chain volume and discloses wash and bot activity as a risk instead.

A program stored on a blockchain that runs automatically when predefined conditions are met — the self-executing infrastructure underneath stablecoins, agent identity, and on-chain payments.

A digital currency pegged to a stable reference asset — typically the US dollar — that functions as the primary settlement infrastructure for both human and machine-to-machine payments in the machine economy.

A fully reserved, regulated digital dollar issued by Circle, pegged 1:1 to the US dollar — the primary settlement asset for on-chain, agent-to-agent machine payments.

An open standard that lets AI agents and software systems pay for digital services directly over HTTP, using stablecoins, without human approval.

An independent, public analytics explorer for the x402 payment protocol — the primary source for tracking on-chain machine-payment volume, transaction counts, and active agents.