# Multi-Engine Metasearch (SERP Multi)

> Multi-Engine Metasearch (SERP Multi) is a paid API for AI agents from api.kadec0.xyz, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Fans out a single query across 2-3 search engines (Brave, Yahoo, Yandex) and returns deduplicated, consensus-ranked results via reciprocal-rank fusion with per-engine rank attribution.

## Facts

- Endpoint: GET https://api.kadec0.xyz/v1/serp-multi
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/multi-engine-metasearch-serp-multi-d8419a76
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_J9mtgMOsqwlxVNrrhGAl3

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 multi-engine-metasearch-serp-multi-d8419a76
```

Example prompt: Search for 'best open-source LLM frameworks 2024' using Brave, Yahoo, and Yandex in web mode with moderate safesearch, limited to the past month, returning up to 10 results per engine — and show me a deduplicated consensus ranking across all three.

## When to prefer this

Use this endpoint when you need unbiased, consensus-ranked web search results that reduce the influence of any single engine's ranking algorithm. It is the right choice when completeness and coverage matter — catching results that one engine might bury or omit. Prefer it over the single-engine SERP endpoint when query quality and diverse ranking perspectives outweigh the slightly higher cost and latency of fanning out to multiple engines. Especially valuable for research, fact-checking, or any task where search bias is a concern.

## Known failure modes

- Invalid engine name supplied — only brave, yahoo, yandex (web) or bing, yahoo (news) are valid
- Fewer than 2 engines specified — minimum is 2
- num_results exceeds cap of 25 per engine
- Invalid timelimit value — must be d, w, m, or y
- Region/locale format not recognized
- Payment not received or insufficient — x402 payment required
- One or more upstream engines temporarily unavailable, reducing result coverage

## How this service works

Multi-engine web search (metasearch). One search query fanned out across 2-3 search engines (Brave, Yahoo, Yandex) with results deduplicated by URL and merged by reciprocal-rank fusion: consensus ranking across engines instead of one engine's bias, with per-engine rank attribution on every result.

## Output

A deduplicated list of web results ranked by reciprocal-rank fusion across the requested engines, each result carrying its title, URL, snippet, and per-engine rank attribution showing which engines surfaced it and at what rank.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "q",
      "engines"
     ],
     "properties": {
      "q": {
       "type": "string",
       "description": "search query"
      },
      "mode": {
       "enum": [
        "web",
        "news"
       ],
       "type": "string",
       "default": "web"
      },
      "region": {
       "type": "string",
       "default": "us-en",
       "description": "locale, e.g. us-en, uk-en, de-de"
      },
      "engines": {
       "type": "string",
       "description": "comma list of 2-3 engines: yahoo, yandex (web mode). news mode has a single live engine (bing), so multi-engine is web-only"
      },
      "timelimit": {
       "enum": [
        "d",
        "w",
        "m",
        "y"
       ],
       "type": "string",
       "description": "restrict to past day/week/month/year"
      },
      "safesearch": {
       "enum": [
        "on",
        "moderate",
        "off"
       ],
       "type": "string",
       "default": "moderate"
      },
      "num_results": {
       "type": "string",
       "default": "10",
       "description": "max results per engine, cap 25"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/multi-engine-metasearch-serp-multi-d8419a76/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.kadec0.xyz](https://www.zero.xyz/host/api.kadec0.xyz/llms.txt)