Multi-Engine Web Search
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.
The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Live 402 challenge
Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.
{
"error": "Payment required",
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x4df66B6c140778fe0717880A7c6dDE5Ea53AcDeA",
"amount": "50000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
}
],
"resource": {
"url": "https://api.kadec0.xyz/v1/serp-multi",
"tags": [
"search",
"web-search",
"serp",
"metasearch",
"multi-engine"
],
"mimeType": "application/json",
"description": "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.",
"serviceName": "Multi-Engine Web Search"
},
"extensions": {
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"q": "best vector database 2026",
"engines": "yahoo,yandex"
}
},
"output": {
"type": "json",
"example": {
"count": 2,
"items": [
{
"type": "serp_multi",
"query": "best vector database 2026",
"engines": [
{
"engine": "yahoo",
"resultCount": 10
},
{
"engine": "yandex",
"resultCount": 10
}
],
"mergedCount": 14
},
{
"url": "https://example.com/vectordb",
"rank": 1,
"type": "search_result",
"title": "Vector DB Comparison",
"engines": [
"yahoo",
"yandex"
],
"snippet": "A comparison of...",
"engineRanks": {
"yahoo": 1,
"yandex": 3
}
}
]
}
}
},
"schema": {
"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"
}
}
}
}
}
}
},
"x402Version": 2
}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
Pay 0.05 USDC on Base to 0x4df6…AcDeA. The signed payment is good for 5 minutes.
- Paid to
- 0x4df6…AcDeA
- USD Coin contract
- 0x8335…02913
- Payment window
- 5 minutes
- As published
- 50000 smallest units
The catalog’s raw entry
[
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x4df66B6c140778fe0717880A7c6dDE5Ea53AcDeA",
"amount": "50000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"q": "best vector database 2026",
"engines": "yahoo,yandex"
}
},
"output": {
"type": "json",
"example": {
"count": 2,
"items": [
{
"type": "serp_multi",
"query": "best vector database 2026",
"engines": [
{
"engine": "yahoo",
"resultCount": 10
},
{
"engine": "yandex",
"resultCount": 10
}
],
"mergedCount": 14
},
{
"url": "https://example.com/vectordb",
"rank": 1,
"type": "search_result",
"title": "Vector DB Comparison",
"engines": [
"yahoo",
"yandex"
],
"snippet": "A comparison of...",
"engineRanks": {
"yahoo": 1,
"yandex": 3
}
}
]
}
}
},
"schema": {
"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"
}
}
}
}
}
}
}Provenance
- Seen in the source catalog
- 2026-09-15 16:57Z
- Last indexed by Roundhouse
- 2026-09-24 14:50Z
- Last enriched (probe, favicon, geo)
- 2026-09-22 06:45Z
- x402 version
- 2
- Max timeout
- 300s
- Liveness probe
- HTTP 402
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 30 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service Multi-Engine Web Search and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=Multi-Engine%20Web%20Search' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://api.kadec0.xyz/v1/serp-multi, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402, or use an organization key from https://roundhouseai.io/dashboard/team. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.