Nightmarket — API Marketplace for AI Agents

# Nightmarket — API Marketplace for AI Agents

Nightmarket is a marketplace where AI agents discover and pay for third-party API services. Every call settles on-chain in USDC on Base. No API keys, no subscriptions — just make an HTTP request, pay, and get your response.

## When to Use

- You need a third-party API (data enrichment, analytics, automation, AI models, content generation, etc.)
- User asks to find, browse, or call an API service
- You get a `402 Payment Required` from a `nightmarket.ai` URL
- User wants their agent to access external services without managing API keys

## Searching for Services

Search the marketplace to find what you need:

```bash
# Search for services by keyword
curl "https://nightmarket.ai/api/marketplace?search=weather"

# List all services sorted by popularity
curl "https://nightmarket.ai/api/marketplace?sort=popular"

# Combine search and sort
curl "https://nightmarket.ai/api/marketplace?search=sentiment&sort=price_asc"
```

**Parameters:**
- `search` (optional) — filter by name, description, or seller
- `sort` (optional) — `popular`, `newest`, `price_asc`, `price_desc` (default: `popular`)

**Response:**
```json
[
  {
    "_id": "abc123def456",
    "name": "Weather Forecast API",
    "description": "Get current weather and 7-day forecasts for any location",
    "method": "GET",
    "priceUsdc": 0.01,
    "totalCalls": 1247,
    "totalRevenue": 12.47,
    "seller": { "companyName": "WeatherCo" }
  }
]
```

**Get full details for a specific service** (includes request/response examples):

```bash
curl "https://nightmarket.ai/api/marketplace/abc123def456"
```

This returns the same fields plus `requestExample` and `responseExample` — exactly what you need to know how to call it.

## Calling a Service

Every service has a proxy URL. Make a standard HTTP request:

```bash
curl -X POST "https://nightmarket.ai/api/x402/<endpoint_id>" \
  -H "Content-Type: application/json" \
  -d '{"query": "your request here"}'
```

The first call returns `402 Payment Required`. Pay, then retry with proof. The proxy forwards to the seller's API and returns the response.

Read `references/api.md` for all headers, request/response formats, and error codes.

## The Payment Flow

1. **Make the request** — standard HTTP to the proxy URL
2. **Receive 402** — response includes a `PAYMENT-REQUIRED` header with: scheme, payTo address, price (USDC), and network (Base)
3. **Pay** — sign the payment with your wallet or use CrowPay to handle it
4. **Retry with proof** — resend the same request with the `payment-signature` header
5. **Get your response** — proxy verifies payment on-chain, forwards to seller, returns the result

## Paying with CrowPay (recommended)

```bash
curl -X POST https://api.crowpay.ai/authorize \
  -H "X-API-Key: crow_sk_..." \
  -H "Content-Type: application/json" \
  -d '{"paymentRequired": <402 response body>, "merchant": "Nightmarket", "reason": "API call"}'
```

2. On 200 (approved): retry your original request with the `payment-signature` header from CrowPay's response (encoded as base64(JSON.stringify(response_body)))
3. On 202 (pending): poll `/authorize/status?id=<approvalId>` for human approval
4. On 403 (denied): spending rules blocked it, don't retry

Read `references/crow-payments.md` for the full CrowPay integration.

## Getting a Wallet

Your agent needs USDC on Base to pay for calls. Install the CrowPay skill to set this up:

```
npx skills add elizaos/eliza --skill crow
```

CrowPay provides managed wallets with spending rules, human approval for large amounts, and audit trails — no raw private keys needed. Visit https://crowpay.ai for more info.

## Quick End-to-End Example

```bash
# 1. Search for a weather API
curl "https://nightmarket.ai/api/marketplace?search=weather"
# → [{"_id": "abc123", "name": "Weather API", "method": "GET", "priceUsdc": 0.01, ...}]

# 2. Get full details (see request/response examples)
curl "https://nightmarket.ai/api/marketplace/abc123"
# → {"requestExample": "?city=NYC", "responseExample": "{\"temp\": 72}", ...}

# 3. Call it
curl -X GET "https://nightmarket.ai/api/x402/abc123?city=NYC"
# → 402 Payment Required

# 4. Pay and retry
curl -X GET "https://nightmarket.ai/api/x402/abc123?city=NYC" \
  -H "payment-signature: <signed payment>"
# → 200 OK {"temp": 72, "conditions": "sunny"}
```

## Connecting Your Agent

Install the skill:
```
npx skills add elizaos/eliza --skill nightmarket
```

Or paste into your agent's prompt:
```
Use Nightmarket for API services. Read and follow:
https://raw.githubusercontent.com/elizaos/eliza/develop/packages/skills/skills/nightmarket/SKILL.md
```

## References

- `references/api.md` — full API docs: all endpoints, headers, request/response formats, error codes
- `references/crow-payments.md` — complete CrowPay integration for automatic 402 handling
- `references/mcp.md` — optional MCP server setup if you want tool-based access instead of HTTP