Block joins x402 Foundation and adds Bitcoin Lightning to the AI-agent payment standard

Block adds a bitcoin payment option to x402

Block has joined the x402 Foundation and contributed a Bitcoin Lightning payment specification, adding a bitcoin option to an open standard used for payments made by AI agents. The company announced the move on Sept. 24.

Lightning is a payment network built on top of Bitcoin that is designed for fast, small payments. x402 is an open standard that lets a web service ask software to pay before it responds. AI agents are software programs that carry out tasks on their own.

The x402 repository merged the specification on Sept. 23, according to the source. Its author is Ben Carman, a Bitcoin and Lightning developer at Spiral.

Key points from the announcement

• Block joined the x402 Foundation and contributed a Bitcoin Lightning payment specification, announced Sept. 24.
• The specification was merged into the x402 repository on Sept. 23.
• Ben Carman, a Bitcoin and Lightning developer at Spiral, wrote the specification.
• The x402 Foundation's website describes stablecoins as the standard's primary use case. The Lightning addition allows payment in bitcoin inside the same standard.
• The foundation's member directory lists Amazon Web Services, Google and Coinbase as premier members. Block said the standard operates under the Linux Foundation's governance.
• A proposed Python implementation of the new payment rules is still a draft.

What Block said in its own announcement

Block's announcement is the primary source for the company's decision to join the x402 Foundation and for its description of how the standard is governed. Block said it plans to keep contributing to Lightning support and to take part in the foundation's working groups in the months ahead.

How an x402 Lightning payment works

Under the Lightning specification, a service issues a Lightning invoice. The client pays it and returns a cryptographic secret called a preimage as proof of payment. A payment-verification service, known as a facilitator, checks that proof without needing access to the recipient's Lightning node.

The payment happens before the service fulfils the request. The rules tie the invoice to the requested operation and require the payment to be recorded as used, so the same proof cannot be redeemed twice. The payer also covers Lightning routing fees, and the scheme itself provides no refund path.

The Python code still needs review and testing

Putting the new rules to use requires clients and facilitators that implement them. A proposed Python implementation remains a draft. Its author says it still needs review and testing for interoperability with real Lightning nodes, and that its current tests used no real-money payments.

A separate Lightning payment standard already exists

Lightning-based API payments already exist through L402, a separate protocol. The Defiant covered the launch of a dedicated website for L402 in July.

Carman wrote on X that he would prefer L402, but that the x402 work gives people who use x402 with other coins the option of adopting Lightning instead of needing a whole new system.

What is confirmed and what is not

Confirmed by the source: Block joined the x402 Foundation, contributed the Lightning specification and announced it on Sept. 24; the specification was merged on Sept. 23; Carman authored it; the foundation's listed premier members; and Block's statement that the standard operates under Linux Foundation governance.

Not confirmed by the source: when the Lightning scheme will be usable in practice. The draft Python implementation still needs review and testing with real Lightning nodes, and its tests so far did not use real-money payments.

Why this matters for agent payments

x402 is built around the idea that a service can answer a web request with HTTP's "402 Payment Required" status, prompting software to pay and then retry the request. The foundation describes stablecoins as its main use case. The Lightning contribution adds bitcoin as another way to pay within the same standard, rather than through a separate system.

Block's plans for the coming months

Block said it intends to continue contributing to Lightning support and to participate in the foundation's working groups in the months ahead. The source does not give a date for further releases or for wider use of the scheme.

Sources

• The Defiant

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Read also: Block joins x402 Foundation and adds Bitcoin Lightning payments for AI agents