agentapi

# AgentAPI

A curated directory of APIs designed for AI agents. Machine-readable. MCP-compatible. Agent-accessible.

**Website:** https://agentapihub.com  
**Billing API:** https://api.agentapihub.com  
**Docs:** https://api.agentapihub.com/api/docs

## x402 Pay-Per-Use Billing

AgentAPI supports **x402** — a payment protocol that lets AI agents pay for API calls with USDC on Base. No API keys required.

### How It Works

1. Agent calls API endpoint (e.g., `/api/gemini/chat/completions`)
2. Server returns `402 Payment Required` with price + wallet address
3. Agent sends USDC payment on Base chain
4. Agent retries with payment proof in header
5. Server verifies payment, proxies request, returns response

### Example Flow

```bash
# 1. Initial request returns 402
curl https://api.agentapihub.com/api/gemini/chat/completions \
  -H "Content-Type: application/json" \
  -d '{"model":"gemini-2.0-flash","messages":[{"role":"user","content":"Hello"}]}'

# Response: 402 Payment Required
# {
#   "price": "0.001",
#   "currency": "USDC",
#   "chain": "base",
#   "recipient": "0xcCb92A101347406ed140b18C4Ed27276844CD9D7",
#   "paymentId": "pay_abc123"
# }

# 2. Agent pays on Base, retries with proof
curl https://api.agentapihub.com/api/gemini/chat/completions \
  -H "Content-Type: application/json" \
  -H "X-Payment-Proof: 0x..." \
  -d '{"model":"gemini-2.0-flash","messages":[{"role":"user","content":"Hello"}]}'
```

### Available x402 APIs

| API | Endpoint | Price |
|-----|----------|-------|
| Gemini Chat | `/api/gemini/chat/completions` | ~$0.001/req |
| Gemini Embeddings | `/api/gemini/embeddings` | ~$0.0005/req |

### Why x402?

- **No API keys** — Agents self-provision access
- **Pay-per-use** — No subscriptions, no minimums
- **Crypto-native** — USDC on Base (fast, cheap txns)
- **Agent-friendly** — Programmatic payments without human bottleneck

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