# Blockscout Arbitrum Messages To Rollup

> Blockscout Arbitrum Messages To Rollup is a paid API for AI agents from api.blockscout.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).

Retrieves messages sent to the Arbitrum rollup layer on a specified blockchain, including origination and completion transaction details

## Facts

- Endpoint: GET https://api.blockscout.com/%7Bchain_id%7D/api/v2/main-page/arbitrum/messages/to-rollup
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/blockscout-arbitrum-messages-to-rollup-cfdaabe6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IoK3YFwwEurV6Wm7Z2ClJ

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-arbitrum-messages-to-rollup-cfdaabe6
```

Example prompt: Can you pull the list of messages sent to the Arbitrum rollup on chain ID 1 using Blockscout, so I can see the origination and completion transaction hashes?

## When to prefer this

Use this endpoint when you specifically need to retrieve messages flowing toward the Arbitrum rollup layer from an L1 or parent chain, including both pending and completed cross-chain messages. Prefer this over generic transaction search endpoints when you need structured bridge message data with origination and completion linkage. Choose this over block explorers' web UI when you need programmatic access to Arbitrum rollup message data at scale.

## Known failure modes

- Invalid chain_id returns an error or empty result
- Messages with no completion yet may have null completion_transaction_hash
- Rate limits or payment failures return 402 Payment Required
- Non-existent or unsupported chain IDs may return 404 or empty items array
- Network timeouts if the Blockscout node for the chain is unavailable

## 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 JSON array of items, each containing origination_timestamp (when the message was sent), origination_transaction_hash (source chain tx hash), origination_transaction_block_number (block number on source chain), and completion_transaction_hash (rollup-side tx hash confirming delivery).

## 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": {
      "chain_id": {
       "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": [
   {
    "origination_timestamp": "string",
    "completion_transaction_hash": "string",
    "origination_transaction_hash": "string",
    "origination_transaction_block_number": 0
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/blockscout-arbitrum-messages-to-rollup-cfdaabe6/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)