The internet is shifting from human users to autonomous AI agents as first-class economic participants. These agents browse the web, call APIs, rent compute, purchase data, and consume services, but today they have no native way to pay. Every transaction requires a human to pre-configure billing, manage API keys, or authorize charges.

Cross Protocol is the payment infrastructure layer built for this shift. It gives AI agents a unified, on-chain way to execute both one-time payments and recurring subscriptions: permissionlessly, transparently, and at Robinhood Chain’s native speed (finality in roughly 400ms) and cost (roughly $0.00025 per transaction).

What Cross provides

For AI agent developers, Cross gives your agents the ability to pay for services autonomously, without human intervention or brittle workarounds. Agents can discover pricing from any Cross-compatible service, authorize a subscription on-chain, and have billing handled automatically from that point forward.

For service providers, Cross gives you a billing layer that works natively with agent traffic. Publish a pricing plan on-chain, add a middleware gate to your API, and start collecting from both human and agent clients, without managing API keys or manual invoices.

Key capabilities

Capability	Description
One-time payments	x402-compatible per-request payment flow
Subscription plans	On-chain plan registry with automatic renewal
Allowances	Metered spend caps for usage-based billing
Payment sessions	High-frequency session tokens with batch settlement (coming in GA)
Webhooks	Structured lifecycle events for your infrastructure

How it works

Cross sits between agents and the services they pay for. Service providers publish pricing plans to the on-chain Cross Plan Registry. When an agent requests a paid resource, the service responds with a 402 Payment Required and the relevant plan terms. The agent (via the Cross SDK) reads those terms, authorizes the payment or subscription on-chain, and receives access.

The full architecture is documented in Architecture.

What Cross is not

Cross is not a wallet. It is not a stablecoin. It is not a layer-1 blockchain. It is billing infrastructure, designed to sit alongside existing wallets, tokens, and services. In spirit it is closer to Stripe than to any blockchain protocol.

Standards compatibility

Cross is a first-class implementation of x402, the HTTP-native payment protocol that originated at Coinbase in May 2025 and is now governed by the x402 Foundation under the Linux Foundation, with participants including Google, Visa, Stripe, AWS, Mastercard, Microsoft, Shopify, and Circle. Cross is also designed to be compatible with MPP (Machine Payments Protocol), the IETF-tracked standard published by Stripe and Tempo in March 2026. Read more in x402 Compatibility and MPP Compatibility.

Get started

If you are building an AI agent and want it to pay for services:

1. Read the Quickstart
2. Install the Agent SDK
3. Review Plans and Subscriptions

If you are a service provider who wants to accept payments from agents:

1. Read the Quickstart
2. Install the Provider SDK
3. Create a plan and add the payment gate middleware

Beta scope

Cross is in public beta. The following are available now: one-time payments via the x402 flow, subscription plans, fixed allowances, the TypeScript SDK, the Cross Dashboard, and USDC on Robinhood Chain mainnet. During beta, the Facilitator is operated by Cross as a centralized service.

Protocol fees are 0.5% of transaction value for one-time payments, 0.3% per subscription billing cycle settled, and 0.2% of session volume. Plan Registry listing is free during beta.

Payment sessions, the Python SDK, the decentralized facilitator network, USDT support, and cross-chain support are all on the roadmap for general availability and beyond.