📚 Knowledge base

Learn agentic finance

Plain-English, sourced explainers for the AI-agent money economy — the standards, the wallets, the settlement layer, and how they compare.

Concepts

What is x402?

x402 is an open protocol that revives HTTP status 402 so any API or website can charge an AI agent a stablecoin micropayment per r…

What is AP2 (Agent Payments Protocol)?

AP2 is Google's open protocol for authorizing AI-agent spending through verifiable mandates. What it does, how it differs from x40…

What is ACP (Agentic Commerce Protocol)?

ACP is the Stripe/OpenAI-backed protocol for agent-driven checkout inside chat surfaces. How it works and how it compares with x40…

What are agentic payments?

Agentic payments are transactions initiated by AI agents rather than humans. The market, the rails (x402, Agent Pay, Intelligent C…

What is an AI agent wallet?

An agent wallet lets an AI agent spend within programmable limits without holding your private keys. Key models (MPC, smart accoun…

What are machine-to-machine (M2M) payments?

How machine payments clear: quote → pay → verify → settle → receipt. Networks, assets, facilitators, and why 98.6% settles in USDC…

What is pay-per-crawl?

Pay-per-crawl lets websites return a machine-readable price to AI crawlers and agents instead of a paywall or a block. How Cloudfl…

What is an x402 facilitator?

A facilitator verifies and settles x402 payments so servers don't need to run blockchain infrastructure. What facilitators do, who…

Agentic payments statistics (2026)

Every key number on AI-agent payments in one place: 169M cumulative transactions, $8B→$1.5T spend forecast, 98.6% USDC share, aver…

What is agentic commerce?

Agentic commerce is buying and selling conducted by AI agents on a person's behalf — discovery, cart, checkout, and payment. How i…

Why do AI agents pay in stablecoins?

98.6% of machine payments settle in USDC. The four reasons stablecoins won agent payments — speed, cost, programmability, regulato…

Guides

Comparisons