@rma-dev/http-proxy-util

TypeScript library that wraps any HTTP API behind machine payments.

npm install @rma-dev/http-proxy-util mppx stripe

The minimum

Seven lines. Any unpaid request gets a 402 with a Stripe payment challenge; paid requests are forwarded to your origin.

import { createProxy } from '@rma-dev/http-proxy-util'

const proxy = createProxy({
  stripe: { secretKey: process.env.STRIPE_SECRET_KEY! },
  origin: 'https://api.yourservice.com',
  routes: [{ method: 'POST', path: '/v1/infer', amount: '0.05' }],
})
Bun.serve({ fetch: proxy.fetch })

Multiple routes

Wildcard * matches one path segment. Unlisted routes are forwarded free.

const proxy = createProxy({
  stripe: { secretKey: process.env.STRIPE_SECRET_KEY! },
  origin: 'https://api.yourservice.com',
  routes: [
    { method: 'POST', path: '/v1/infer',  amount: '0.05', description: 'Single inference' },
    { method: 'GET',  path: '/v1/data/*', amount: '0.01' },
  ],
})

Add Tempo (crypto) payments

Include a tempo block to accept PATH stablecoin alongside Stripe. Callers see both options and pick whichever their wallet supports.

const proxy = createProxy({
  stripe: { secretKey: process.env.STRIPE_SECRET_KEY! },
  tempo:  { recipient: process.env.TEMPO_RECIPIENT as `0x${string}`, testnet: true },
  origin: 'https://api.yourservice.com',
  routes: [
    {
      method: 'POST',
      path:   '/v1/infer',
      pricing: {
        stripe: { amount: '0.05', currency: 'usd' },
        tempo:  { amount: '0.04' },   // slightly cheaper to incentivise crypto
      },
    },
  ],
})

Add Base USDC payments

const proxy = createProxy({
  stripe: { secretKey: process.env.STRIPE_SECRET_KEY! },
  base: {
    payTo:   process.env.BASE_PAY_TO as `0x${string}`,
    network: 'base-sepolia',   // 'base' for mainnet
  },
  origin: 'https://api.yourservice.com',
  routes: [
    {
      method: 'POST',
      path:   '/v1/infer',
      pricing: {
        stripe: { amount: '0.05', currency: 'usd' },
        base:   { amount: '0.05' },
      },
    },
  ],
})

All three payment methods

Accept Stripe card, Tempo crypto, and Base USDC simultaneously.

const proxy = createProxy({
  stripe: { secretKey: process.env.STRIPE_SECRET_KEY! },
  tempo:  { recipient: process.env.TEMPO_RECIPIENT as `0x${string}`, testnet: true },
  base:   { payTo: process.env.BASE_PAY_TO as `0x${string}`, network: 'base-sepolia' },
  origin: 'https://api.yourservice.com',
  routes: [
    {
      method:      'POST',
      path:        '/v1/infer',
      description: 'Single inference request',
      pricing: {
        stripe: { amount: '0.05', currency: 'usd' },
        tempo:  { amount: '0.04' },
        base:   { amount: '0.05' },
      },
    },
    {
      method: 'GET',
      path:   '/v1/data/*',
      pricing: {
        stripe: { amount: '0.01', currency: 'usd' },
        tempo:  { amount: '0.008' },
        base:   { amount: '0.01' },
      },
    },
  ],
})

Framework adapters

All adapters delegate to proxy.fetch.

// Bun
Bun.serve({ port: 3000, fetch: proxy.fetch })

// Hono
app.all('*', (c) => proxy.fetch(c.req.raw))

// Express
app.use(proxy.express())

// Next.js App Router  (app/api/[[...path]]/route.ts)
export const { GET, POST, PUT, PATCH, DELETE } = proxy.nextjs()

// Cloudflare Workers / Deno
export default { fetch: proxy.fetch }

Built-in endpoints

| Path | Description | |---|---| | /llms.txt | Human/LLM-readable pricing and billing info | | /__stripe-proxy/discover | JSON pricing discovery per route | | /__stripe-proxy/health | Liveness probe | | /api/stripe-proxy/create-spt | Test SPT for browser flows (test mode only) |

_meta in request bodies

The proxy reads a _meta object from JSON bodies for customer enrichment, then forwards the full body — including _meta — to the origin unchanged.

{
  "prompt": "Hello",
  "_meta": {
    "email": "[email protected]",
    "payment_intent_metadata": { "tenant": "acme" }
  }
}

Configuration reference

createProxy(options)

| Option | Type | Description | |---|---|---| | stripe | StripeConfig? | Stripe card / Link payments | | tempo | TempoConfig? | Tempo crypto (PATH stablecoin) payments | | base | BaseConfig? | Base USDC payments | | origin | string | Upstream service base URL | | routes | RoutePriceConfig[] | Per-route pricing table | | services | Record<string, ServiceConfig>? | Named sub-services at /{id}/* | | title | string? | Proxy name — surfaced in /llms.txt | | description | string? | Short description — surfaced in /llms.txt | | blockUnlistedRoutes | boolean? | 404 for routes not in the table (default false) | | paymentMetadata | Record<string, string>? | Static metadata on every PaymentIntent | | createCustomers | boolean? | Stripe customer reconciliation (default true) | | sptEndpoint | string \| null? | Test SPT path (default /api/stripe-proxy/create-spt) |

StripeConfig

| Field | Type | Description | |---|---|---| | secretKey | string | sk_test_… or sk_live_… | | networkId | string? | Stripe Business Network profile ID ('internal' for test) | | paymentMethodTypes | string[]? | Default: ['card', 'link'] |

TempoConfig

| Field | Type | Description | |---|---|---| | recipient | `0x${string}` | Wallet address that receives PATH payments | | testnet | boolean? | Use Tempo testnet (default false) | | currency | string? | PATH token address (defaults to PATH_USD) |

BaseConfig

| Field | Type | Description | |---|---|---| | payTo | `0x${string}` | EVM wallet that receives USDC | | network | string? | 'base', 'base-sepolia' (default), or EIP-155 chain ID | | facilitatorUrl | string? | Payment verification URL (default: https://x402.org/facilitator) |

RoutePriceConfig

| Field | Type | Description | |---|---|---| | method | string | HTTP method or '*' | | path | string | URL path — supports a single * wildcard per segment | | description | string? | Human-readable label in the payment challenge | | amount | string? | Flat Stripe price in USD (e.g. '0.05') | | currency | string? | Currency for flat amount (default 'usd') | | pricing | RoutePricing? | Per-method pricing (overrides amount/currency) | | free | boolean? | Forward without a payment gate | | requireEmail | boolean? | Require _meta.email in the request body | | requirePhone | boolean? | Require _meta.phone in the request body | | requireBillingAddress | boolean? | Require _meta.billing_address | | schema | RouteSchema? | Zod-compatible validators for body/query |

RoutePricing

| Field | Type | Description | |---|---|---| | stripe | { amount: string; currency: string }? | Stripe card price | | tempo | { amount: string }? | Tempo price in PATH units | | base | { amount: string }? | Base price in USD (converted to USDC internally) |

Peer dependencies

mppx   >=0.6.0
stripe >=17.0.0