What is x402 payment protocol?

x402 is a payment protocol built by Stripe and Coinbase that enables AI agents to pay for API requests directly with cryptocurrency. It allows seamless machine-to-machine payments without API keys or accounts.

How do AI agents pay with Apiosk?

AI agents can pay through Apiosk using USDC on Base through x402 or SEPA-funded balances. The gateway verifies payment, applies spend controls, executes the paid action, and records settlement state.

What is an x402 payment gateway?

An x402 payment gateway like Apiosk processes HTTP 402 payment flows from AI agents and software systems. It handles payment verification, spend controls, execution, settlement, and logs.

How do I integrate Apiosk?

Use the direct gateway API for maximum control, the JavaScript SDK for application code, the remote MCP endpoint for chat-native agent clients, or the gateway skill for coding-agent runtimes.

Install Apiosk

Integrations

Connect agents, apps, and backends to Apiosk through direct HTTP, MCP, the JavaScript SDK, or the gateway skill. Pick the path based on where the software runs and how much control you need.

Direct HTTP

Gateway API

What: The raw payment gateway surface for HTTP 402 payment challenges, x402 proofs, connect-token execution, request logs, and settlement state.

When: Use this when you own the backend or agent runtime and want the most explicit control over headers, retries, policies, and ledger events.

Why: It is the lowest-level path. You keep your app and product flow while Apiosk handles payment verification and money movement.

How

1Call your protected route through the gateway.
2Handle the HTTP 402 response when payment is required.
3Attach an x402 payment proof, connect token, or other supported payment authorization.
4Retry the request and inspect the response headers and ledger logs.

Endpoint

https://gateway.apiosk.com

Read Gateway Docs

ChatGPT + agent clients

Remote MCP Endpoint

What: A hosted MCP endpoint that lets compatible agent clients connect to Apiosk without hand-writing raw HTTP calls.

When: Use this for ChatGPT-style clients, GPT-native tools, or agent environments where OAuth and hosted tool execution are easier than direct gateway headers.

Why: It reduces integration friction for chat-native workflows while keeping payment execution tied to Apiosk accounts and controls.

How

1Add the remote MCP URL in the client.
2Complete the hosted OAuth flow once.
3Run paid tools from the same chat or agent session.
4Use dashboard logs to inspect spend, payment rail, and execution state.

Remote URL

https://mcp.apiosk.com/mcp

Open MCP Endpoint

@apiosk/sdk

JavaScript SDK

What: A package for application code that wraps payment execution, typed 402 errors, auth modes, and retry helpers.

When: Use this when you are building a Node.js backend, workflow runner, or product integration and want less manual payment plumbing.

Why: It keeps payment logic consistent across your app while still letting you decide when an agent is allowed to spend.

How

1Install the package.
2Configure your gateway base URL and auth mode.
3Call execute helpers from your backend or workflow engine.
4Catch typed 402 errors and retry with the right payment authorization.

Install

npm install @apiosk/sdk

Read SDK Docs

skills.sh

Gateway Skill

What: An installable skill for coding-agent runtimes that need to execute paid gateway requests from a shell-first workflow.

When: Use this for Codex, Claude Code, and similar coding agents where a skill can hold the operational instructions and commands.

Why: It gives agents a repeatable payment workflow without each repo inventing its own gateway wrapper.

How

1Install the skill in the supported agent runtime.
2Import or configure the Apiosk connect token.
3Let the agent execute paid gateway requests with explicit spend boundaries.
4Review generated commands and gateway logs when debugging.

Install

npx skills add Apiosk/openclaw-apiosk --skill apiosk-gateway

Clone Starter Kit

Choose the path

Which integration should you install?

You control the backend

Gateway API or JavaScript SDK

You are inside ChatGPT or a hosted agent client

Remote MCP Endpoint

You are using a coding agent

Gateway Skill or MCP server

You need a working reference app

x402 Starter Kit

You need maximum control over payment headers

Gateway API

MCP setup

Agent client commands

Claude Code

claude mcp add apiosk -- npx -y apiosk-mcp-server

Codex

codex mcp add apiosk -- npx -y apiosk-mcp-server

ChatGPT-compatible MCP client

https://mcp.apiosk.com/mcp

Connect

Choose direct HTTP, SDK, MCP, or skill based on where the agent is running.

Authorize

Use wallet payment proofs, connect tokens, OAuth, or dashboard-backed sessions.

Execute

The agent hits a paid route, resolves the 402 requirement, and retries with payment attached.

Control

Budgets, approvals, rail rules, and logs keep autonomous spend bounded.

Settle

Apiosk records balances, pay-ins, payouts, reconciliation, and settlement state.

Example payload

What a paid agent execution looks like

The shape is the same across integrations: a tool or route is called, payment state is attached or resolved, and the result includes enough context to audit the transaction.

{
  "tool": "paid-action",
  "input": {
    "operation": "POST /execute",
    "amount": "0.42",
    "rail": "USDC or SEPA-funded balance"
  },
  "response": {
    "status": "success",
    "payment_rail": "x402",
    "ledger_event": "settled",
    "result": {
      "access": "granted"
    }
  }
}

Start with Apiosk

Ready to move money for autonomous software?

Add SEPA and USDC payment rails, enforce spend controls, and settle agent transactions through one gateway.

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