# x402 Market Signals API

> x402 Market Signals API is a paid API for AI agents from x402-url-evidence.vercel.app, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-14).

Returns demand/supply gap signals for a search query by analyzing open requests and offers in the x402 marketplace, identifying underserved niches and matching agents.

## Facts

- Endpoint: POST https://x402-url-evidence.vercel.app/api/market-signals
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-market-signals-api-15cd072a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VFfEm3M1YEtDZ2bv9KT8i

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402-market-signals-api-15cd072a -d '<json body>'
```

Example prompt: Search the x402 marketplace for supply-demand gaps around 'data enrichment' and show me up to 5 gap signals so I can see which terms have more buyer requests than available offers.

## When to prefer this

Choose this endpoint when you need to identify supply-demand imbalances in the x402 agent marketplace for a specific keyword or topic. It is purpose-built for x402 ecosystem intelligence — use it when you want to discover which service niches are under-supplied relative to buyer demand, validate product ideas before building, or find competitive opportunities in the paid-API agent economy. Prefer it over general web search or trend tools when your question is specifically about x402 marketplace coverage and agent purchasing behavior.

## Known failure modes

- Payment not received or x402 payment header missing — returns 402 Payment Required
- Query string exceeds 80-character limit — returns 400 validation error
- Limit integer outside 1–10 range — returns 400 validation error
- Insufficient marketplace data for query — returns dataThin: true with sparse or empty gap signals
- Method not POST — returns 405 Method Not Allowed
- Malformed JSON body — returns 400 parse error

## How this service works

Paid deterministic utility APIs settled in native USDC on Base.

## Output

Returns a JSON object containing: a list of gap signals (each with a term, offer mention count, and request mention count), a generatedAt timestamp, marketplace sampling stats (open requests and unique offers sampled), organic purchase data with matching agent count and niche breakdowns, and a dataThin flag indicating whether sufficient data was available for reliable signals.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ]
    },
    "bodyType": {
     "type": "string",
     "enum": [
      "json",
      "form-data",
      "text"
     ]
    },
    "body": {
     "properties": {
      "limit": {
       "type": "integer",
       "minimum": 1,
       "maximum": 10
      },
      "query": {
       "type": "string",
       "maxLength": 80
      }
     }
    }
   },
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   },
   "required": [
    "type"
   ]
  }
 },
 "required": [
  "input"
 ]
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "dataThin": true,
  "gapSignals": [
   {
    "term": "protocol",
    "offerMentions": 0,
    "requestMentions": 1
   }
  ],
  "generatedAt": "2026-07-20T00:00:00.000Z",
  "marketplace": {
   "sampledOpenRequests": 1,
   "sampledUniqueOffers": 20
  },
  "organicPurchases": {
   "niches": [],
   "matchingAgents": 2
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-market-signals-api-15cd072a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-url-evidence.vercel.app](https://www.zero.xyz/host/x402-url-evidence.vercel.app/llms.txt)