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🤝 Agent-to-Agent Payments

A2A payments

When one autonomous agent pays another for data, compute, or a finished task — settled in USDC over x402, with no human approving each transaction.

198
A2A projects tracked
USDC
settlement currency
HTTP 402
payment handshake

What are A2A payments?

Agent-to-agent (A2A) payments are transactions between two autonomous AI agents — a buyer and a seller — with no human in the loop. As agents specialize (one holds data, another a model, another a set of tools), they need a way to pay each other on demand rather than through pre-arranged human contracts and API keys.

The settlement layer is almost always x402: the seller agent returns an HTTP 402 response with payment terms, the buyer\u2019s agent wallet pays USDC, and the request is fulfilled — typically in seconds. Discovery and messaging may use Google\u2019s A2A Protocol or MCP, but those don\u2019t move money on their own.

How an A2A payment works

1

Agent A needs a service

A buyer agent wants data, compute, or a completed task from another agent (the seller).

2

Seller asks to be paid

The seller agent’s endpoint replies with HTTP 402 and payment terms — an amount in USDC and where to send it.

3

Buyer pays from its wallet

Agent A’s wallet signs and sends the USDC payment, then retries the request with proof of payment.

4

Service is delivered

A facilitator verifies settlement and the seller fulfills the request — all in seconds, with no human in the loop.

A2A payment projects

Real projects from the directory · stars live from GitHub · sorted by popularity.

A local-first AI agent with persistent memory, emotional intelligence, and a peer-to-peer skills economy.

⭐ 2.4kTypeScript

The trust layer for agent-to-agent commerce — natural-language mandates, ERC-7710 delegated permissions, x402 payments, escrow, and dispute resolution as one open, catch-all Agent Skill / Claude Code plugin.

⭐ 1.1kTypeScript

Agent behavior that compiles

⭐ 566Rust

The A2A x402 Extension brings cryptocurrency payments to the Agent-to-Agent (A2A) protocol, enabling agents to monetize their services through on-chain payments. This extension revives the spirit of HTTP 402 "Payment Required" for the decentralized agent ecosystem.

⭐ 541Python

Aser is a lightweight, self-assembling AI Agent frame.

⭐ 470Python

Golang SDK for A2A Protocol

⭐ 421Go

A small, powerful, open-source CLI coding agent that works with open models.

⭐ 295Python

AI agents platform that gives you a workspace with an integrated team of personal assistants that can work behind the scenes to handle daily monotonous tasks.

⭐ 208Python

Lucid Agents Commerce SDK. Bootstrap AI agents in 60 seconds that can pay, sell, and participate in agentic commerce supply chains. Our protocol agnostic SDK provides CLI-generated templates and drop-in adapters for Hono, Express, Next.js, and TanStack, giving you instant access to crypto/fiat payment rails (AP2, A2A, x402, ERC8004).

⭐ 189TypeScript

An operating system built for AI agents — talk to your NixOS server instead of SSH-ing in. Typed, audited tool access with atomic rollback on every change. Research-grade; run it on a disposable box, not production.

⭐ 112Rust

A complete TypeScript implementation of the Python x402 payment protocol extension for A2A (Agent-to-Agent) communication. Enable your AI agents to request, verify, and settle crypto payments seamlessly.

⭐ 103TypeScript

Connect AI agents across any network — zero config, encrypted, skill-based routing

⭐ 77Shell

Browse all 198 A2A projects →

Frequently asked questions

What is A2A (agent-to-agent) payments?

A2A payments are transactions where one autonomous AI agent pays another for a service — data, compute, or a finished task — without a human approving each payment. The payment rail is usually x402: the seller agent returns HTTP 402, the buyer agent's wallet pays USDC, and the service is delivered. We track 198 A2A projects in the directory.

How is A2A different from the A2A Protocol by Google?

Google’s A2A (Agent2Agent) Protocol standardizes how agents discover and communicate with each other. It does not itself move money. A2A payments add the settlement layer — typically x402 — so that once two agents agree on a task, one can actually pay the other.

Why do agents need to pay each other directly?

In a multi-agent system, agents specialize: one has data, another has a model, another has tools. Letting them pay per request — instead of pre-arranging human contracts and API keys — lets capabilities be composed on demand and priced by usage.

What stops an agent from overspending?

Agent wallets enforce policy: per-call limits, daily caps and allow-lists. See our AI agent wallet guide. The payment itself is logged on-chain, giving an auditable trail of every A2A transaction.

What protocol do A2A payments use?

Most use x402 for settlement because it works over plain HTTP and settles USDC in seconds. Discovery and messaging may use the A2A Protocol or MCP. See our x402 guide and A2A vs x402 comparison for how the pieces fit.

See also: A2A vs x402 · AI agent payments · agent wallets · AP2