HTTP 402 protocol

HTTP 402 is the web-native standard for payments. Our mission is to design a frictionless machine-to-machine protocol that allows agents to pay for APIs, compute resources, and data using simple HTTP requests and native blockchain transactions scaling to billions of sub-cent microtransactions.

This unlocks a previously unattainable economic layer for AI-native commerce, while simultaneously delivering a best-in-class user experience for humans.

// This is an example of how our package can be integrated with NextJS middleware
// You can check out the sections below to find more implementation options
// Or reach out to us at [email protected]
export const middleware = h402NextMiddleware({
  routes: {
    "/api/paywalled_route": {
      paymentRequirements: [
        {
          namespace: "evm",
          tokenAddress: "0x55d398326f99059ff775485246999027b3197955", // USDT on BSC
          tokenDecimals: 18,
          tokenSymbol: "USDT",
          amountRequired: 0.01, // 0.01 USDT
          amountRequiredFormat: "humanReadable",
          payToAddress: "0xd78d20FB910794df939eB2A758B367d7224733bc",
          networkId: "56", // BSC Chain ID
        },
      ],
    },
  }
});

export const config = {
  matcher: ["/api/paywalled_route"],
};

This protocol builds on top of the scheme from x402, to ensure the continuation and adoption of a true open standard. You can check our FAQs to learn more.

Supported networks and schemes

Currently, h402 supports:

Networks:

• All EVM-compatible chains (Ethereum, Binance Smart Chain, Base, etc.)
• Solana (mainnet)
• Arkade (Bitcoin mainnet)

Payment Types:

• Signed payloads (permit-based tokens like USDC)
• Broadcasted transactions (for tokens like USDT and native currencies like BNB/ETH)
• Solana transactions with memo (for SOL and SPL tokens)
• Arkade transactions

Payment schemes:

• exact: Fixed amount payments with predefined values

We're actively expanding support for additional networks, tokens, and payment schemes. See our roadmap for upcoming implementations including Bitcoin, and new payment models like upto, streamed, and subscription.

Protocol

HTTP 402 is the web-native standard for payments. Our mission is to design a frictionless machine-to-machine protocol that allows agents to pay for APIs, compute resources, and data using simple HTTP requests and native blockchain transactions, scaling to billions of sub-cent microtransactions.

This unlocks a previously unattainable economic layer for AI-native commerce, while simultaneously delivering a best-in-class user experience for humans.

We decided to create h402, which simply stands for HTTP 402, based on the open schemes provided by x402.

The reason for spinning off into a separate project comes down to a few key points, you can read them in our FAQs.md or at our website h402.xyz.

We're a fairly small team, so this repo is evolving rapidly we'll be updating it weekly (or even daily) with new details, schemes, and examples. In the meantime, if anything's missing or underspecified, you can check out the original x402 repository for reference. Eventually, this message will disappear because we genuinely believe this will become the leading implementation of the 402 protocol, or we will find a way to merge with x402.

Example Next application

In the example/ folder we've provided a simple demo of a Next webapp integrating both the facilitator (server) and the client to restrict access to a specific page under a 402 payment required response.

It works utilizing this package and its functionalities and provides a quick example of how such an integration can be made, including the UI for the wallet connection & send.

Development Setup

This project is set up as a pnpm monorepo workspace, allowing for seamless development across multiple packages.

Prerequisites

• Node.js (see .nvmrc for version)
• pnpm package manager

Workspace Structure

The monorepo contains the following workspaces:

• typescript/package: The main @bit-gpt/h402 package
• typescript/example: Example Next.js application using the package
• typescript/facilitator: Facilitator implementation

Getting Started

1. Install dependencies:

   pnpm install
   

2. Run the example application:

   pnpm dev:example
   

Development Workflow

The monorepo is configured with the following workflow:

1. Dependency Management:

   • All dependencies are hoisted to the root node_modules directory
   • Workspace packages reference each other using workspace:* syntax
   • No need for manual linking between packages

2. Build Process:

   • pnpm build: Builds all packages in the monorepo (use when you need to build everything)
   • pnpm build:package: Builds only the main @bit-gpt/h402 package (sufficient for most development)
   • pnpm clean: Cleans build artifacts from all packages

3. Development Commands:

   • pnpm dev:example: Builds the main package and starts the example Next.js application
   • Changes to the package code require rebuilding before they're available to the example

4. Configuration:

   • The root .npmrc file contains important configuration for the monorepo
   • pnpm-workspace.yaml defines the workspace package locations

Adding New Packages

To add a new package to the monorepo:

1. Create a new directory in the appropriate location
2. Add a package.json with the package details
3. Add the package path to pnpm-workspace.yaml
4. Run pnpm install to update the workspace

Troubleshooting

If you encounter "Module not found" errors when running the example:

1. Make sure all packages are built: pnpm build
2. Check that the package exports are correctly defined in the package.json
3. Verify that the imports in your code match the export paths

Current schemes and types

The only available scheme for now is exact, the types are the following.

All the types can be found here

FAQs

See FAQs.md or our website h402.xyz

Roadmap

See ROADMAP.md.

Community

Join our Discord community to stay up to date, contribute to feature development, and connect directly with our team.

Playground

See PLAYGROUND.md.

License

The h402 protocol is licensed under the Apache-2.0 license.