x402 Product Reputation API

A pay-per-call product reputation intelligence API monetized via the x402 protocol. AI agents and developers pay USDC micropayments to get structured reputation analysis of any product, powered by community data from Reddit, Hacker News, and YouTube.

Architecture

┌─────────────┐     HTTP 402      ┌──────────────────┐
│  AI Agent /  │ ◄──────────────► │  x402 Reputation │
│  Developer   │   USDC payment   │     API Server   │
└─────────────┘                   └────────┬─────────┘
                                           │
                    ┌──────────────────────┼──────────────────────┐
                    ▼                      ▼                      ▼
             ┌──────────┐         ┌──────────────┐       ┌──────────────┐
             │  Reddit   │         │  HN Algolia  │       │   YouTube    │
             │  JSON API │         │   Search API │       │  Transcripts │
             └──────────┘         └──────────────┘       └──────────────┘
                    │                      │                      │
                    └──────────────────────┼──────────────────────┘
                                           ▼
                                  ┌──────────────────┐
                                  │  Claude Sonnet   │
                                  │  (LLM Analysis)  │
                                  └──────────────────┘
                                           │
                                           ▼
                                  ┌──────────────────┐
                                  │ Structured Report │
                                  │ Score + Dimensions│
                                  │ + Competitor Map  │
                                  └──────────────────┘

Endpoints & Pricing

Endpoint	Price (USDC)	Description
POST /analyze	$0.05	Full reputation report with dimensional scoring
POST /compare	$0.08	Head-to-head comparison of 2-5 products
POST /monitor	$0.03	Quick 7-day sentiment pulse
GET /health	Free	Service info + Bazaar metadata

Quick Start

1. Install

git clone <your-repo>
cd x402-reputation-api
npm install

2. Configure

cp .env.example .env
# Edit .env with your:
#   - WALLET_ADDRESS (your EVM address for receiving USDC)
#   - ANTHROPIC_API_KEY (for LLM analysis)
#   - NETWORK (eip155:84532 for testnet, eip155:8453 for mainnet)

3. Run

# Development
npm run dev

# Production
npm run build && npm start

4. Test with x402 client

# Get testnet USDC from https://faucet.circle.com/
EVM_PRIVATE_KEY=0x... npx tsx test-client.ts

API Reference

POST /analyze

Full reputation analysis with dimensional scoring.

Request:

{
  "product": "Supabase",
  "competitors": ["Firebase", "PlanetScale"],
  "timeRange": "90d",
  "sources": ["reddit", "hn", "youtube"],
  "category": "devtools"
}

Response:

{
  "product": "Supabase",
  "overallScore": 78,
  "overallSentiment": "positive",
  "confidence": 0.72,
  "dimensions": [
    {
      "dimension": "Developer Experience",
      "score": 85,
      "sentiment": "positive",
      "evidence": [
        "Community frequently praises migration from Firebase as seamless",
        "Documentation quality cited as standout feature"
      ],
      "sampleSize": 34
    },
    {
      "dimension": "Pricing",
      "score": 72,
      "sentiment": "mixed",
      "evidence": [
        "Free tier widely praised, but scaling costs concern some users",
        "Comparisons to PlanetScale pricing are common"
      ],
      "sampleSize": 18
    }
  ],
  "sources": [
    { "source": "reddit", "postsAnalyzed": 89, "avgSentiment": 0.3 },
    { "source": "hn", "postsAnalyzed": 45, "avgSentiment": 0.2 }
  ],
  "competitors": [
    {
      "product": "Firebase",
      "overallScore": 65,
      "strengthVs": ["Ecosystem integration", "Mobile SDK maturity"],
      "weaknessVs": ["Vendor lock-in concerns", "Pricing transparency"],
      "dimensions": { "Developer Experience": 70, "Pricing": 55 }
    }
  ],
  "totalDataPoints": 134,
  "generatedAt": "2026-03-20T12:00:00.000Z"
}

POST /compare

Head-to-head comparison of multiple products.

Request:

{
  "products": ["Vercel", "Netlify", "Cloudflare Pages"],
  "timeRange": "90d",
  "sources": ["reddit", "hn"],
  "category": "devtools"
}

POST /monitor

Quick 7-day sentiment pulse (cheaper, faster).

Request:

{
  "product": "Cursor",
  "sources": ["reddit", "hn"]
}

Data Sources

Source	API	Auth	Rate Limit
Hacker News	Algolia Search API	None	10,000 req/hr
Reddit	Public JSON API	None (OAuth optional)	~60 req/min
YouTube	Invidious API → Transcripts	None	Varies by instance

Deployment

Deploy to Railway / Render / Fly.io

Standard Node.js deployment. Set environment variables and expose port 4021.

Switch to Mainnet

In .env:

NETWORK=eip155:8453
FACILITATOR_URL=https://x402.org/facilitator
# Add CDP API keys if using Coinbase facilitator for mainnet

Register on Bazaar

When using the CDP facilitator, your endpoints are automatically discoverable via the x402 Bazaar. The config.description, inputSchema, and outputSchema in the payment middleware are used for service discovery.

For AI Agents

This API is designed for autonomous AI agent consumption:

1. Agent discovers the API via Bazaar or direct URL
2. Agent sends request → receives 402 with payment instructions
3. Agent's x402 client auto-pays USDC and retries
4. Agent receives structured JSON reputation data

No accounts, no API keys, no subscriptions — just HTTP + USDC.

Category Options

Use the category field to tune subreddit selection:

• default — General tech
• saas — SaaS products
• devtools — Developer tools
• ai — AI/ML products
• crypto — Crypto/Web3
• hardware — Physical products
• fintech — Financial technology

License

MIT