Three weeks ago, we analysed how x402 gave the internet a native payment layer built on stablecoins. One week later, we covered how Stripe's Machine Payments Protocol added fiat, BNPL, and bitcoin settlement on top. Both protocols answered the same question: how does an AI agent pay for something?

Neither answered the question before it: what does the agent pay from?

MoonPay just answered that. On March 23, the company open-sourced the Open Wallet Standard (OWS), a specification for how AI agents create wallets, manage keys, sign transactions, and hold value across every major blockchain. It is released under an MIT licence, available on GitHub, npm, and PyPI.

The problem OWS solves is specific and unsolved until now.

An AI agent that needs to transact on a blockchain faces a key management problem. It needs a private key to sign transactions. But exposing a private key to an agent process, or worse, to the large language model context driving that agent, is a security risk that no serious deployment can accept. Agents get prompt-injected. Agents hallucinate. Agents run in shared environments. Handing them raw access to signing keys is the crypto equivalent of writing your bank password on a sticky note and handing it to an intern.

OWS separates the agent from the key. Private keys are encrypted at rest using AES-256-GCM, decrypted only to produce a signature, held in protected memory that cannot be swapped to disk, and wiped immediately after signing. The agent never sees the key. It requests a signature through the OWS interface, and the standard handles the cryptography in isolation.

A single seed phrase derives accounts across eight chain families: EVM, Solana, Bitcoin, Cosmos, Tron, TON, Spark, Filecoin, and XRP Ledger. One wallet, one interface, eight networks. The standard uses CAIP-2 chain identifiers, the same cross-chain addressing scheme that x402's V2 specification adopted for multi-chain support.

The policy engine is where operational control lives. Before any transaction is signed, OWS evaluates it against configurable rules: spending limits, contract allowlists, chain restrictions, and time-bound authorisations. This is the layer where a business sets guardrails on what an agent can spend, where it can spend, and when.

MoonPay did not build this from scratch for the open-source release. In February 2026, the company launched MoonPay Agents, a non-custodial software layer that gives AI agents access to wallets and the ability to transact autonomously via MoonPay's CLI. OWS is that wallet infrastructure generalised across chains and runtimes, then released under an open licence for anyone to use.

"The agent economy has payment rails. It didn't have a wallet standard. We built one, open-sourced it, and now the full stack exists," Ivan Soto-Wright, CEO and co-founder of MoonPay, said in the announcement.

The contributor list is broad. Over 15 organisations contributed to the standard before launch: PayPal, OKX, Ripple, Circle, Ethereum Foundation, Solana Foundation, TON Foundation, Base, Polygon, Sui, Filecoin Foundation, Arbitrum, LayerZero, Tron, Dynamic, Dflow, Uniblock, Virtuals, Allium, and Simmer.Markets.

"Nobody building a serious agent is going to limit it to one chain. The Open Wallet Standard treats every network as a first-class citizen, and that's why TON is contributing to it," Max Crown, President and CEO of TON Foundation, said.

The presence of PayPal and Circle is notable. PayPal operates one of the largest consumer payment platforms in the world. Circle issues USDC, the stablecoin that x402 uses as its primary settlement token. Their contribution to OWS suggests they see agent wallet infrastructure as a layer worth standardising rather than competing on.

Here is where the pieces fit together. We have been mapping the agentic commerce stack all quarter. Discovery, trust, processing, settlement. But settlement always assumed the agent had a way to hold value. That assumption is now a specification.

Layer 1: The wallet. OWS gives an agent a secure place to hold funds across multiple chains. One seed, eight networks, keys never exposed. This is the foundation.

Layer 2: The payment protocol. x402 embeds stablecoin payments into HTTP itself. A server returns a 402 status code with payment metadata. The agent signs a transaction and pays in the same request cycle. Stripe's MPP does the same but settles on stablecoins, cards, BNPL, or bitcoin depending on what the merchant accepts.

Layer 3: The merchant integration. MPP connects to Stripe's 4.5 million merchants. x402 connects to any HTTP endpoint. OpenAI's Agent Commerce Protocol and Google's Universal Commerce Protocol handle discovery and checkout.

OWS explicitly designed for this interoperability. The press release names x402, MPP, Google's AP2, and ERC-8004 as complementary protocols. The use case is straightforward: an agent holds balance in an OWS vault, receives an x402 payment request, the policy engine checks spending limits, the wallet signs the transaction with the key isolated from the agent process, and the signature is returned. The agent paid for a service without ever touching a private key.

The wallet standard solves key management. It does not solve the harder questions.

Custody and liability. If an agent's OWS wallet is drained through a prompt injection attack that bypasses the policy engine, who bears the loss? The agent operator? MoonPay? The protocol that routed the payment? OWS encrypts keys and enforces spending limits, but no policy engine is perfect. The liability framework for autonomous agent wallets does not exist yet.

Fiat on-ramps. OWS manages crypto wallets. For an agent to hold value in those wallets, someone needs to fund them. MoonPay's core business is fiat-to-crypto conversion, which positions them well here, but the standard itself does not specify how wallets get funded. An agent with an empty wallet and a valid x402 payment request still cannot pay.

Adoption versus fragmentation. OWS has 15 contributors. That is impressive for a launch-day specification. But the crypto industry has a long history of open standards that fragment rather than unify. Whether OWS becomes the default or one of several competing agent wallet standards depends on whether the major agent frameworks, Anthropic's MCP, OpenAI's function calling, Google's agent toolkit, adopt it as their wallet layer.

The demand question. x402 processes roughly $28,000 in daily volume, much of it testing. MPP launched with zero volume history. OWS launched with zero agents using it in production. The entire three-layer stack is infrastructure ahead of demand. That is either prescient engineering or three solutions looking for a problem at the same time.

The timing is the story. In the span of one month, three different companies shipped three different layers of the same stack.

Coinbase and the x402 Foundation shipped the payment protocol. Stripe and Tempo shipped the merchant integration and multi-rail settlement. MoonPay shipped the wallet standard. None of them coordinated. Each built to solve the problem they understood best.

This is how infrastructure gets built. Not by committee, not by a single company designing the whole stack, but by multiple companies building layers that turn out to be complementary. TCP/IP, HTTP, and HTML were not designed by the same team. They were designed by different teams solving different problems, and the internet emerged from the seams.

The agent economy's financial infrastructure is following the same pattern. The wallet layer, the payment protocol, and the merchant integration are now all open standards. The question is no longer whether agents can pay for things. The plumbing exists. The question is whether enough agents need to pay for enough things to justify the plumbing.

The wallet, the protocol, and the merchant layer all shipped in March 2026. When every piece of the stack exists but no one is using it yet, who moves first: the agents, the merchants, or the customers funding the wallets?