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GlosarioAgent-to-Agent (A2A) Transactions
Agent-to-Agent (A2A) Transactions
Agent-to-agent (A2A) transactions are interactions in which autonomous AI agents discover, coordinate, and execute exchanges with one another, under predefined rules.
What Are Agent-to-Agent (A2A) Transactions?
Agent-to-agent (A2) transactions are interactions in which autonomous
AI agents discover, coordinate, and execute exchanges with one another, under predefined rules.
When Did A2A Transactions Begin to Occur?
Agent-to-agent (A2A)
transactions emerged from the convergence of machine-to-machine communication, advances in AI, and programmable digital payments.
Protocols helped computers exchange information online, while the HTTP 402 status code introduced an early template for payment-gated web access.
However, HTTP 402 remained mostly unused until newer protocols, such as x402, applied it to machine-to-machine payments. As machine-payment protocols matured, public
ledgers made digital assets programmable and AI systems became more capable, giving AI agents more ability to act as independent economic participants.
How Do A2A Transactions Work?
A2A transactions work by allowing AI agents to send messages, verify permissions, and exchange value through programmable digital systems, often using
microtransactions.
This enables agents to control digital
wallets, execute transactions through smart contracts, and exchange assets in real time. However, processing these transactions at scale requires shared standards for identity, messaging, authorization, reputation, and payment.
These standards help agents identify one another, coordinate actions, and exchange value
interoperably across different ecosystems. For example, x402 and MPP enable programmatic payments over HTTP, while ERC-8004 defines onchain primitives for agent identity, reputation, and validation without relying on one central authority.
To operate responsibly, A2A systems also need guardrails such as spending limits,
audit trails, policy enforcement, verifiable identities, and human override mechanisms.
Why Does Blockchain Matter for A2A Transactions?
Blockchain can help A2A transactions by giving agents access to
programmable payments, transparent records, and user-controlled assets.
In closed platforms, agents may be limited by
permissioned environments, closed APIs, opaque fees, or platform-specific rules. Open blockchain infrastructure can reduce those limits by allowing agents to interact across services and ecosystems.
Smart contracts can define transaction rules in code, while tokens and stablecoins can support instant digital payments. Public blockchains can also make agent activity easier to audit.
How Could Agents Transform the Digital Economy?
A2A transactions could reshape the digital economy by enabling
AI agents to participate directly in digital workflows and markets as independent economic actors.
Instead of requiring centralized intermediaries or human approval for each step, agents can independently discover services, negotiate terms, and complete transactions directly with one another. For example, an AI agent could pay for a data feed, call a specialized API, or contract another agent to complete a task.
Author
Dr. David Minarsch is CEO of
Valory and a founding member of
Olas, the blockchain-based AI agent platform behind Pearl, an AI agent app store that lets users own their agents. His team also released Polystrat, an autonomous AI agent that trades on Polymarket on behalf of its users.
Dr. Minarsch holds a PhD in applied game theory from the University of Cambridge and works on open, decentralized frameworks that help AI agents operate transparently and in users’ interests.