Google launches Agent Payments Protocol

Edition 121 | September 22, 2025

I know way too many websites that would probably run faster on a vape than whatever they’re running on now.

Welcome back to Building AI Agents, your biweekly guide to everything new in the field of agentic AI!

Google staked its claim to the new agent economy, launching a payments protocol that it hopes will be the universal standard for agentic transactions.

In today’s issue…

• Google releases the Agent Payments Protocol

• Alibaba open-sources a rival to OpenAI’s Deep Research

• Why you should be re-writing your prompts

• The rise of virtual agent economies

• Stop calling your AI agents “teammates”

…and more

🔍 SPOTLIGHT

After winning the last round of the great agent protocol war, Google is doubling down.

Last Tuesday, the tech giant released Agent Payments Protocol (AP2), a standardized, open-source framework for agents to transact with each other and with vendors. The protocol operates through Mandates—digital cryptographic contracts that represent promises to buy or sell goods at a given price. In an example of a typical transaction, a user instructs their agent to buy a jacket of a specific type at a certain price or less, the agent searches for the product, and contracts with the merchant via AP2 to buy it.

This isn’t Google’s first rodeo with agent protocols. Earlier this year, they launched Agent2Agent (A2A), a similar open-source standard intended to be the universal protocol for agents built with any software to communicate with each other. Of course, Google’s assertion that the agentic world should use their protocol wouldn’t guarantee that it would catch on, which is why they released A2A in collaboration with a massive coalition of Fortune 500 partners in an attempt to create unstoppable momentum. It seems to have worked: although A2A isn’t quite universally accepted as the agent-agent communication standard, it’s definitely the leading one.

Unsurprisingly, Google is running the same playbook with AP2, bringing over 60 household name companies onboard, including nearly every major payment provider such as PayPal, American Express, Discover, Mastercard, and more.

AP2’s launch is the latest step towards a new internet of agents, where our online tasks are increasingly performed by AIs acting on our behalf. Research and question-answering were first—many people (including yours truly) turn to ChatGPT Deep Research or Perplexity for answers to complex questions requiring web browsing. Actual commerce has lagged a bit behind—letting an agent spend your money is much higher-stakes than asking it to find the best activities in Nashville. But people are clearly already using them to find products: a mind-blowing 1/3 of all product searches now come from agents. Giving them the power to actually buy is just one step further.

It’s too early to tell whether AP2 will catch on, but if Google’s previous success with A2A is anything to go off of, they’ve got a good shot. In 2028, when your shopping agent is booking your next hotel—or when your sales agent is closing a deal with a customer to buy your product—there’s a decent chance it’ll be using AP2.

Always keep learning and building!

—Michael

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