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API and Integrations

Emerging Payment Protocols#

Agents can already call APIs. The harder part is paying for them without human checkout, long-lived billing setup, or broad custody. Machine-payment protocols try to put payment into the same request flow as access.

Hightop's role is the account and control layer behind those flows. The agent still pays from the same Hightop account, inside the same lane, under the same permissions and limits.

Where Hightop Is Today#

x402 is documented as a callable Hightop route:

text
example
POST https://api.hightop.com/api/actions/x402/sign

It is agent-callable and launch-ready, but it is not a /v1/agent/* endpoint and does not create an AgentOperation.

MPP is not yet in the Agent API. Treat it as an emerging protocol direction, not a callable Hightop API surface today.

What x402 Is#

x402 is a payment protocol built around HTTP 402 Payment Required. A service can return payment requirements, the client can obtain a payment authorization, and the original request can be retried with payment attached.

In Hightop, the current x402 route signs a USDC payment authorization on Base from a per-wallet signer EOA. Hightop may top up that signer from the Hightop wallet, returns a payment header, and records settlement as Activity.

See x402 Payments and Pay with x402.

What MPP Is#

MPP, short for Machine Payments Protocol, is an emerging machine-payments protocol from Stripe and Tempo. It is aimed at machine-to-machine payment flows that may include API access, agent-to-agent commerce, micropayments, or recurring usage.

MPP is not a current Agent API endpoint. Hightop can support additional machine-payment surfaces as they become real and useful, but builders should not design against an MPP Hightop route until one is published.

Why These Protocols Matter#

Most web commerce assumes a human:

  • creates an account
  • enters a card
  • chooses a plan
  • manages billing
  • handles failed payment recovery

Agents need lower-friction payment flows. A research agent buying one data query or an operations agent paying for one tool call should not need a new billing relationship every time.

How They Fit Hightop#

Machine-payment protocols sit at the edge of Hightop. They do not replace the Hightop account, wallet, rules, monitoring, or revocation model.

text
example
agent
  -> machine-payment protocol
  -> Hightop account and controls
  -> stablecoin settlement

The protocol can change. The Hightop lane still controls what the agent is allowed to spend, where, and under what limits.

Where to Go Next#

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x402 Payments

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API Reference