# Blockscout Arbitrum Withdrawal Messages by Transaction Hash

> Blockscout Arbitrum Withdrawal Messages by Transaction Hash is a paid API for AI agents from api.blockscout.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-12).

Retrieves Arbitrum L2-to-L1 withdrawal message details for a specific transaction hash on a given chain

## Facts

- Endpoint: GET https://api.blockscout.com/%7Bchain_id%7D/api/v2/arbitrum/messages/withdrawals/%7Btransaction_hash%7D
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/blockscout-arbitrum-withdrawal-messages-by-transaction-hash-e0742326
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VnIeu4SU4eoN_bfLiY9RL

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-withdrawal-messages-by-transaction-hash-e0742326
```

Example prompt: Can you look up the Arbitrum withdrawal messages for transaction hash 0xabc123...def456 on Arbitrum One (chain ID 42161) and tell me the withdrawal status and whether there's a completion transaction?

## When to prefer this

Use this endpoint when you specifically need to inspect Arbitrum L2-to-L1 withdrawal message data tied to a known transaction hash, including status, token details, and finalization info. Prefer this over generic blockchain explorers when you need structured, machine-readable withdrawal message data rather than human-readable explorer pages, and when you are operating on Arbitrum or other chains supported by Blockscout.

## Known failure modes

- Invalid or non-existent transaction hash returns empty items array or 404
- Unsupported chain_id returns an error or empty response
- Transaction hash is not an Arbitrum withdrawal transaction — no messages returned
- Network timeout or Blockscout API unavailability returns 5xx error
- Malformed transaction hash format returns validation error

## 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 list of Arbitrum withdrawal message objects, each containing a message ID, raw data, token info (name, symbol, decimals, amount, address, destination), withdrawal status, callvalue, L2 timestamp, Arbitrum block number, Ethereum block number, caller address hash, destination address hash, and completion transaction hash.

## 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"
      },
      "transaction_hash": {
       "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": [
   {
    "id": 0,
    "data": "string",
    "token": {
     "name": "string",
     "amount": "string",
     "symbol": "string",
     "decimals": 0,
     "address_hash": "string",
     "destination_address_hash": "string"
    },
    "status": "string",
    "callvalue": "string",
    "l2_timestamp": 0,
    "arb_block_number": 0,
    "eth_block_number": 0,
    "caller_address_hash": "string",
    "destination_address_hash": "string",
    "completion_transaction_hash": "string"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/blockscout-arbitrum-withdrawal-messages-by-transaction-hash-e0742326/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)