# Trend Then SERP Intent

Give a keyword, get its trend series and the current Google results.

- endpoint: `GET https://marketplaceforaiagents.com/api/public/v1/trend-then-serp`
- category: intents
- price: $0.005 USDC per call (5000 atomic, 6 decimals)
- free tier: 3 calls per agent identity, shared across all endpoints (unknown/generic clients draw from a site-wide 100 successful free calls per UTC day; crawlers get none)
- settlement: USDC on Base mainnet `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`, payee `0x05e82e03753c7bc99fb24d10a876cce53f24b7b7`, scheme `exact`
- sandbox: append `?network=base-sepolia` for testnet USDC + mock data
- results key: `results`
- html: https://marketplaceforaiagents.com/listings/trend-then-serp

## What it returns

Momentum first, evidence second: Google Trends interest for a keyword plus the live Google SERP for the same term in one call.

## Use cases

- Decide whether a topic is rising before writing
- Keyword prioritization
- Campaign timing checks

## Parameters

| param | type | required | default | description |
| --- | --- | --- | --- | --- |
| `q` | string | yes | — | Keyword to measure and search |
| `geo` | string | no | — | Trends country code, e.g. US |
| `date` | string | no | — | Trends time range, e.g. today 12-m |
| `gl` | string | no | us | Country code for results |
| `hl` | string | no | en | Interface language code |

## Example call

```bash
curl -s "https://marketplaceforaiagents.com/api/public/v1/trend-then-serp?q=example"
```

## Response shape

```json
{
  "intent": "trend-then-serp",
  "chain": [
    "google-trends",
    "google-search"
  ],
  "steps_run": 2,
  "results": {
    "google-trends": {
      "note": "Normalized response of /api/public/v1/google-trends"
    },
    "google-search": {
      "note": "Normalized response of /api/public/v1/google-search"
    }
  }
}
```

## Payment

1. Call without `X-PAYMENT`. The first 3 calls per identity (across all endpoints) return 200 with an `X-Free-Calls-Remaining` header.
2. After that the response is `402` with an `accepts[]` requirement.
3. Sign the EIP-3009 USDC authorization, base64 the x402 payload, resend as `X-PAYMENT`.
4. Settlement receipt returns in the `X-PAYMENT-RESPONSE` header.