How I Built a Pay-Per-Call API Marketplace with x402, PayPal, and Alipay

GoldBean: 47 Endpoints, 3 Payment Methods, Zero API Keys

The Problem

Most AI API services force you into monthly subscriptions. You sign up, get an API key, and pay 0/month even if you only make 10 API calls. That's insane.

The Solution: Pay Per Call

I built GoldBean — an API marketplace with 47 endpoints (OCR, TTS, ASR, LLM Chat, Image Generation, Translation, NLP) where you only pay for what you use. No subscription, no API key required.

Three payment methods, all live:

1. PayPal — Credit card, debit card, or PayPal balance. Buy credits from .
2. Alipay — WeChat Pay, Alipay balance, or bank card. Same credit packs.
3. USDC on Base (x402) — Pay per call directly with crypto. No prepayment needed.

How x402 Works

x402 is an open protocol for HTTP-native payments. When you request a paid endpoint without credentials, you get a response with payment details:

Sign the challenge with your USDC wallet, send the transaction on Base, and retry with the payment header. That's it.

Credit System

• 20 free credits on registration (no payment needed)
• 1 credit = 1 call at the /usr/bin/bash.01 tier (OCR, TTS, NLP)
• 8 credits = 1 call at the /usr/bin/bash.08 tier (LLM Chat)
• Credits never expire

Or go unlimited with membership:

• Monthly: 9.9/mo (all endpoints, 100 req/min)
• Quarterly: 9/3mo (save 23%, 500 req/min)
• Yearly: 69/yr (save 31%, 1000 req/min)

Try It Now

Buy credits or membership — PayPal, Alipay, and USDC all supported.

Tech Stack

• Backend: Node.js + Express, PM2 managed
• Payments: PayPal REST API v2, Alipay SDK, x402/USDC on Base
• AI APIs: Baidu AI (OCR, TTS, ASR, LLM, Image Gen)
• Hosting: AlmaLinux VPS with nginx

All endpoints are live and tested. Give it a try!