# Blockscout Multichain Block Number Search

> Blockscout Multichain Block Number Search is a paid API for AI agents from api.blockscout.com, paid per call via x402, $0.012/call, status unknown (last checked 2026-09-10).

Search for block numbers matching a query across multiple blockchain networks within a cluster using Blockscout's multichain explorer

## Facts

- Endpoint: GET https://api.blockscout.com/services/multichain/api/v1/clusters/%7Bcluster_id%7D/search/block-numbers
- Price: $0.012/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/blockscout-multichain-block-number-search-b2728571
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rz1XgGaN1_OWxQNRDsAzr

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 blockscout-multichain-block-number-search-b2728571
```

Example prompt: Search Blockscout's multichain explorer for block numbers matching '0xabc123' across Ethereum and Arbitrum in cluster 'mainnet-cluster', returning up to 10 results.

## When to prefer this

Use this endpoint when you need to find block numbers across multiple blockchain networks simultaneously using a single query, particularly when you have a cluster_id grouping the chains you care about. Prefer this over single-chain block explorers when doing cross-chain research, auditing, or verification tasks that span EVM-compatible networks.

## Known failure modes

- Invalid or unknown cluster_id returns 404
- Missing required query parameter 'q' may return empty results or error
- Unsupported chain_id values may be silently ignored or return no results
- Payment failure (x402) if USDC balance is insufficient
- Rate limiting if too many requests are made in quick succession
- Large page_size values may be capped or cause slower responses

## How this service works

Explore crypto activities with Blockscout's multichain search. Find transactions, addresses, tokens, and dapps across top blockchain networks — your go-to explorer for cross-chain blockchain data

## Output

Returns a paginated list of items each containing a chain_id and block_number where the search query matched, along with next_page_params (page_token and page_size) for fetching subsequent pages.

## 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"
    },
    "pathParams": {
     "type": "object",
     "properties": {
      "cluster_id": {
       "type": "string"
      }
     }
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "q": {
       "type": "string"
      },
      "chain_id": {
       "type": "array"
      },
      "page_size": {
       "type": "integer"
      },
      "page_token": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "items": [
   {
    "chain_id": "string",
    "block_number": "string"
   }
  ],
  "next_page_params": {
   "page_size": 0,
   "page_token": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/blockscout-multichain-block-number-search-b2728571/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.blockscout.com](https://www.zero.xyz/host/api.blockscout.com/llms.txt)