Introduction

Router402 is a payment-gated API platform that enables developers to access AI models using the x402 HTTP payment protocol. It combines ERC-4337 smart accounts with session keys to provide a seamless, gasless payment experience for AI model inference.

What is Router402?

Router402 provides:

• Payment-Gated AI APIs -- Access top AI models (Claude, Gemini) through a single API with automatic billing via on-chain payments.

• Smart Account Abstraction -- Users interact through Kernel v3.1 smart accounts powered by ZeroDev, with gas fees sponsored by Pimlico.

• Session Keys -- Delegated signing keys that allow your backend to execute transactions on behalf of users without holding their private keys.

• OpenAI-Compatible Chat API -- A drop-in replacement for OpenAI-style chat completion endpoints, with built-in usage tracking and billing.

Architecture Overview

Supported Models

Model	Provider	Input Price	Output Price
anthropic/claude-opus-4.6	Anthropic	$5.00/M	$25.00/M
anthropic/claude-opus-4.5	Anthropic	$5.00/M	$25.00/M
anthropic/claude-sonnet-4.5	Anthropic	$3.00/M	$15.00/M
anthropic/claude-haiku-4.5	Anthropic	$1.00/M	$5.00/M
google/gemini-3-pro-preview	Google	$4.00/M	$18.00/M
google/gemini-3-flash-preview	Google	$0.50/M	$3.00/M

Prices are per million tokens. A 10% commission is applied on top of base costs.

Quick Links

Section	Description
API Reference	REST API endpoints -- authorize, models, and chat completions
SDK Guide	Installation, setup, and usage examples
Architecture	System design, data flows, and technology stack
Setup Flow	Complete user onboarding walkthrough