x402 Bazaar

The decentralized API marketplace where AI agents pay with USDC, not API keys.

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Ecosystem

Repository	Description
x402-backend (this repo)	Backend API — Express server, payment middleware, 112 native wrappers, MCP server
x402-frontend	React frontend — 15 pages, glassmorphism UI, wallet connect, i18n FR/EN
x402-langchain	Python package — LangChain tools for x402 Bazaar (pip install)
x402-fast-monetization-template	FastAPI template — Monetize any Python function with x402 in 5 minutes
CLI: npx x402-bazaar	One-line setup for Claude Desktop, Cursor, VS Code
@x402/sdk	TypeScript SDK — typed client for x402 Bazaar APIs
Reviews API	Ratings & reviews system for marketplace services
Bazaar Discovery	Agent discovery via @x402/extensions v2.5.0 (official Coinbase SDK)

Live: x402bazaar.org | API: x402-api.onrender.com | Dashboard: x402-api.onrender.com/dashboard

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What is x402 Bazaar?

x402 Bazaar is an autonomous API marketplace built on the HTTP 402 Payment Required standard. AI agents discover services, pay in USDC on Base, SKALE on Base (ultra-low gas), or Polygon, and get instant access -- no API keys, no subscriptions, no accounts. The server verifies payments on-chain and enforces anti-replay protection, making every transaction trustless and permissionless.

Key Features

• HTTP 402 Protocol -- Standard-compliant payment flow. Call an endpoint, get a 402 with payment details, pay USDC, retry with tx hash, done.
• 112 Native API Wrappers -- Web search, URL scraper, Twitter/X, weather, crypto, jokes, DALL-E 3, translation, code execution, sentiment analysis, and 100+ more -- all behind micropayments.
• 112+ Registered Services -- Growing marketplace of third-party APIs monetized through x402.
• LangChain Integration -- Python package x402-langchain for agents built with LangChain/LangGraph.
• Multi-Chain -- Base (mainnet) + SKALE on Base (ultra-low gas fees ~$0.0007/tx) + Polygon (mainnet, ~$0.001/tx via MATIC).
• MCP Server -- Plug into Claude Desktop, Cursor, VS Code, or Claude Code as native AI tools.
• One-Line Setup -- npx x402-bazaar init detects your IDE and configures everything.
• Anti-Replay Protection -- Every transaction hash is stored in Supabase and can only be used once.
• Budget Control -- Per-session spending caps for AI agents (configurable MAX_BUDGET_USDC).
• Security Hardened -- Helmet headers, CORS whitelist, rate limiting (3 tiers), input sanitization, SSRF protection.
• 2151 Tests -- 14+ test suites, all passing (node:test, zero deps).
• Real-Time Monitoring -- 112 endpoints checked every 5min, Telegram alerts on transitions, public /api/status page.
• Telegram Bot -- Interactive admin bot with 6 commands (/balance, /stats, /status, /recent, /services, /help).
• Auto-Test on Registration -- New services are pinged automatically, with Telegram notification on result.
• Public Stats -- GET /api/public-stats (no auth) for frontend homepage counters.

Quick Start

# One-line setup for AI IDEs (Claude Desktop, Cursor, VS Code)
npx x402-bazaar init

Or run the server locally:

git clone https://github.com/Wintyx57/x402-backend.git
cd x402-backend
npm install
cp .env.example .env   # Fill in your keys
node server.js

How the x402 Payment Flow Works

Agent                          x402 Bazaar                     Base / SKALE / Polygon
  |                                |                                |
  |  GET /api/weather?city=Paris   |                                |
  |------------------------------->|                                |
  |  402 Payment Required          |                                |
  |  { amount: 0.02, recipient }   |                                |
  |<-------------------------------|                                |
  |                                |                                |
  |  Transfer 0.02 USDC ------------------------------------------>|
  |  tx: 0xabc123...              |                                |
  |                                |                                |
  |  GET /api/weather?city=Paris   |                                |
  |  X-Payment-TxHash: 0xabc123   |                                |
  |------------------------------->|                                |
  |                                |  verify tx on-chain ---------->|
  |                                |  mark tx used (anti-replay)    |
  |  200 OK { temperature: 15.2 } |                                |
  |<-------------------------------|                                |

API Reference

Marketplace Endpoints

Route	Method	Cost	Description
/	GET	Free	Marketplace info + endpoint catalog
/health	GET	Free	Health check + supported networks
/services	GET	0.05 USDC	List all registered services
/search?q=	GET	0.05 USDC	Search services by keyword
/register	POST	1.00 USDC	Register a new service

Native API Wrappers (112 endpoints, x402-powered)

Route	Cost	Source	Description
/api/search?q=	0.005 USDC	DuckDuckGo	Clean web search results for LLMs
/api/scrape?url=	0.005 USDC	Cheerio + Turndown	Any URL to clean Markdown
/api/twitter?user=|tweet=|search=	0.005 USDC	fxtwitter	Twitter/X profiles, tweets, search
/api/weather?city=	0.02 USDC	Open-Meteo	Weather data for any city
/api/crypto?coin=	0.02 USDC	CoinGecko	Cryptocurrency prices (USD/EUR)
/api/joke	0.01 USDC	Official Joke API	Random joke
/api/image?prompt=	0.05 USDC	DALL-E 3	AI image generation (1024x1024)
/api/wikipedia?q=	0.005 USDC	Wikipedia API	Article summaries
/api/dictionary?word=	0.005 USDC	Free Dictionary	English definitions
/api/countries?name=	0.005 USDC	REST Countries	Country data
/api/github?user=|repo=	0.005 USDC	GitHub API	Profiles and repo stats
/api/npm?package=	0.005 USDC	NPM Registry	Package metadata
/api/ip?address=	0.005 USDC	ip-api.com	IP geolocation
/api/translate?text=&to=	0.005 USDC	MyMemory	Translate 90+ languages
/api/summarize?text=	0.01 USDC	GPT-4o-mini	AI text summarization
/api/code	0.005 USDC	Piston API	Execute code in 50+ languages
/api/sentiment?text=	0.005 USDC	GPT-4o-mini	Sentiment analysis
/api/dns?domain=	0.003 USDC	Node DNS	DNS record lookup
/api/currency?from=&to=	0.005 USDC	Frankfurter	Currency conversion (ECB)
...and 22 more	0.003-0.005	Various	See API_WRAPPERS.md

Monitoring & Status (Free)

Route	Description
/api/status	Live monitoring status for all 112 endpoints
/api/status/uptime	Uptime percentages by endpoint
/api/status/history	Check history (last 24h)
/api/public-stats	Public stats (services, API calls, monitoring, integrations)

Dashboard (Admin, requires X-Admin-Token)

Route	Description
/dashboard	Admin UI -- stats, services, activity log, System Info
/api/stats	JSON stats (services, payments, revenue, wallet balance)
/api/analytics	Enriched analytics (balance, recent activity, avg price)

Payment Headers

Header	Required	Description
X-Payment-TxHash	Yes (for paid endpoints)	USDC transfer transaction hash
X-Payment-Chain	No (default: base)	Chain used: base, base-sepolia, skale, or polygon

MCP Server

The MCP server exposes x402 Bazaar as native tools for AI IDEs. Agents can discover, search, and pay for APIs directly from their conversation.

npx x402-bazaar init   # Auto-detects your IDE and installs

MCP Tools (15 total)

Tool	Cost	Description
discover_marketplace	Free	Browse available endpoints and service count
search_services	Free	Search APIs by keyword
list_services	Free	Full service catalog
get_service_schema	Free	Inspect required parameters for a service
find_tool_for_task	Free	Describe what you need in plain English, get the best match
call_service	price_usdc	Call a marketplace service with auto-payment
call_api	Free	Call any external API URL
get_wallet_balance	Free	Check agent wallet USDC balance on-chain
setup_wallet	Free	Configure or create an agent wallet
export_private_key	Free	Export the agent wallet private key
import_openapi	Free	Import an OpenAPI spec as a marketplace service
import_rapidapi	Free	Import a RapidAPI service to the marketplace
create_payment_link	Free	Create a payment link for a service
access_payment_link	Free	Access a payment link
get_budget_status	Free	Session spending tracker

Supported Networks

Network	Chain ID	Gas	USDC Contract
Base	8453	~$0.001	0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
Base Sepolia	84532	Free (testnet)	0x036CbD53842c5426634e7929541eC2318f3dCF7e
SKALE on Base	1187947933	~$0.0007 (CREDITS)	0x85889c8c714505E0c94b30fcfcF64fE3Ac8FCb20
Polygon	137	~$0.001 (MATIC)	0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359

Tech Stack

Layer	Technology
Runtime	Node.js
Framework	Express 5
Blockchain	Base + SKALE on Base + Polygon (USDC)
Wallet SDK	Coinbase Developer Platform (CDP)
Database	Supabase (PostgreSQL)
MCP	Model Context Protocol SDK
AI (demo)	OpenAI GPT-4o-mini
Scraping	Cheerio + Turndown

Environment Variables

Variable	Description
PORT	Server port (default: 3000)
NETWORK	mainnet or testnet
WALLET_ADDRESS	USDC recipient address
WALLET_ID	Coinbase CDP wallet ID
COINBASE_API_KEY	Coinbase Developer Platform API key
COINBASE_API_SECRET	CDP API secret
SUPABASE_URL	Supabase project URL
SUPABASE_KEY	Supabase anon key
OPENAI_API_KEY	OpenAI key (for /api/image, /api/summarize, /api/sentiment)
ADMIN_TOKEN	Secret token for dashboard access
TELEGRAM_BOT_TOKEN	Telegram bot token for monitoring alerts + interactive commands
TELEGRAM_CHAT_ID	Telegram chat ID to receive notifications

Scripts

npm start            # Start the server
npm run mcp          # Start the MCP server
npm run seed         # Seed 112+ services into Supabase
npm run seed:wrappers # Register the 112 native wrappers
npm run demo         # Run the autonomous agent demo
npm run demo:live    # Live demo with terminal UI

Security

• Helmet -- Security headers (HSTS, X-Content-Type, X-Frame-Options)
• CORS -- Strict origin whitelist (no wildcards in production)
• Rate Limiting -- 3 tiers: general (500/15min), paid endpoints (30/min), registration (10/hr)
• Anti-Replay -- Transaction hashes persisted in Supabase used_transactions table
• On-Chain Verification -- Validates USDC transfer logs directly via RPC
• USDC-Only -- Rejects non-USDC token transfers
• Input Sanitization -- Control character rejection, Postgres LIKE escaping, length limits
• SSRF Protection -- Blocks localhost, private IPs, IPv6 loopback, cloud metadata
• Body Limit -- 10KB max request body
• RPC Timeout -- 10s timeout on all blockchain calls

Create Your Own x402 API

Monetize any Python function in 5 minutes with the FastAPI template:

git clone https://github.com/Wintyx57/x402-fast-monetization-template
cd x402-fast-monetization-template
pip install -r requirements.txt
cp .env.example .env  # Set your WALLET_ADDRESS
python main.py

@x402_paywall(price=0.05, description="My API", tags=["cool"])
def my_function(text: str) -> dict:
    return {"result": "something"}

Contributing

Contributions are welcome. Please open an issue to discuss proposed changes before submitting a PR.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Links

• Website: x402bazaar.org
• Frontend: github.com/Wintyx57/x402-frontend
• LangChain: github.com/Wintyx57/x402-langchain
• CLI: npx x402-bazaar init | npm
• API Template: x402-fast-monetization-template
• Live API: x402-api.onrender.com
• Dashboard: x402-api.onrender.com/dashboard

License

MIT