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Payment Channels and x402 Batch Settlement Are Available on Solana

On October 7, Solana said x402 batch payments are available via PayAI and BlockRun. An agent deposits a ceiling, authorizes calls by signature, and settles in bulk. The Foundation measured more than 1 million payments a second in a proxy test.

SOLANA·HUB Editorial
Source: Solana

What Happened

On October 7, at 5:45 a.m. CEST, Solana posted on X that batch payments for x402 are available on Solana through PayAI and BlockRun. Solana describes the flow this way: an agent opens a payment channel, makes as many payments as it needs, and settles once through x402.

The channels under that flow are older. The Solana Foundation described them in a post dated September 3. What that morning added is the report that batch settlement is running with PayAI and BlockRun.

BlockRun had posted at 3:59 a.m. CEST that it shipped batch x402 payments with PayAI and the Solana Foundation. BlockRun says several model calls can be paid with a single USDC transaction. The graphic on that post carries the lines “10x Lower Latency” and “Save $20K+ /mo in Gas Fees.” Those are BlockRun’s own figures, not an independent comparison.

x402 is the protocol in which a service answers an unpaid call with HTTP status 402 and the caller attaches a payment. The per-call flow is explained in AI agents on Solana: x402. The status code stays. What changes is that many authorizations collapse into fewer transactions.

How a Payment Channel Works

An agent deposits a ceiling once into an on-chain escrow. The program holds the funds, not the API operator. Each use is then authorized with a signature, not with its own transaction. One transaction settles the amount actually consumed. Recipients are paid their share. Whatever was not used goes back to the wallet that deposited it.

The Foundation compares this to a bar tab or a prepaid meter. Money goes down up front, usage runs without a payment at every step, and the bill is settled once. The deposit is the cap. The payer pays for what was consumed.

On pay.sh the Foundation adds that the operator can pay the network fee for opening and settling. The payer then needs the stablecoin, not SOL.

Three schemes sit on the same program:

  • x402 “upto”: a ceiling for a single metered call. The operator settles the actual amount and refunds the difference.
  • x402 “batch-settlement”: many deliveries, settled together. The Foundation names this scheme in the September 3 post. PayAI documents it, and the October 7 posts are about this batch flow.
  • MPP “session”: one channel for a stream of deliveries. Each delivery is authorized by a cumulative voucher, and the channel settles once when the session closes after sitting idle.

The program is open source under the MIT license. The repository says it is live on mainnet at CHNLxYvVA28MJP9PrFuDXccuoGXAx7jBacfLEkahyGsX. That address is an executable program on mainnet. The repository links a July 2026 security report from Cantina.

Solana frames that as one settlement. PayAI describes day-to-day operation in more detail. PayAI tells the operator to claim vouchers on a short cadence, for example every 10 to 60 seconds, and to pay out whatever is currently owed. That produces fewer transactions than calls. The docs do not say a channel stays at exactly one transaction for its whole life. PayAI does not store unclaimed vouchers for the operator. Under that description, claiming rarely can mean lost revenue. Once the channel is closed, the repository says the unused remainder comes back immediately. If the depositor forces the close, PayAI sets a waiting period of 15 minutes to 24 hours.

Why It Matters for Agents and Paid APIs

Two patterns fit a transaction per call poorly. One is a call whose price is known only afterward, such as a language model billed per token, or a job billed per byte or per second of compute. The other is many small deliveries, such as a token-by-token reply or a burst of hundreds of cheap calls. A payment channel cuts the on-chain work down to one open and one settle, however often usage is metered in between.

The Foundation names three consequences of settling every call. A person has to approve payments one by one. Every payment adds cost and latency. Prepaid credit, the Foundation writes, leaves the payer’s wallet on the first call and is tracked in someone else’s database. With a payment channel the user sets a cap, the agent spends against it, and the funds stay in the program.

What the Test Measures

In the September 3 post the Foundation writes that a test sent 100,000 distinct wallets through a payment-channel proxy, at more than 1 million payments per second. It calls that enough capacity for more than 80 billion payments in 24 hours, and it states an estimated processing cost of $0.000000000776 per payment.

That is a proxy test. The Foundation describes it that way. It is not a measured count of transactions the Solana network processed at that rate. The Foundation publishes an open-source template and load-testing tools for anyone who wants to reproduce the run.

Limits of the PayAI Preview

PayAI runs the facilitator, the service that submits verification and settlement for the scheme. PayAI says the packages @x402/core and @x402/svm, from version 2.28.0, come from the x402 Foundation repository. PayAI does not publish them.

PayAI calls the support a public preview. The public path needs no PayAI account and no API key. New channels take a deposit of 0.01 to 100 USDC on Solana mainnet. The cap is 10 open or closing channels per operator. With an account, that operator’s API keys share the allowance. Without an account, PayAI counts channels per Solana receiving address. In-flight reservations count. Across the service, PayAI sponsors at most 1,000 channels, open, closing, and reserved together. New channels can be paused when capacity or the funds that cover fees run short. Current values come from the /supported endpoint.

Alibaba Cloud in the September Post

The September 3 post names Alibaba Cloud as a launch partner for payment channels. The Foundation wrote that the API endpoints were reachable that day. An agent authorizes once and calls the APIs without an account of its own and without an approval per call. The October 7 posts do not mention Alibaba Cloud. They do not say whether those endpoints were still reachable on October 8.

Note: This is reporting, not investment advice.

What to Watch

  • Whether PayAI changes the public-preview limits or stops accepting new channels for a time
  • Whether the Foundation or Alibaba Cloud updates the status of those API endpoints after September 3

Sources

#x402 #payments #ai-agents #payai #usdc

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