> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chainstack.com/llms.txt
> Use this file to discover all available pages before exploring further.
# debug_traceBlockByHash | Arbitrum
Arbitrum API method that traces the execution of all transactions in a block identified by its hash. This method provides detailed traces for every transaction and call that took place in the block, including gas usage and performance metrics for each operation.
Learn how to [deploy a node](/docs/debug-and-trace-apis#arbitrum) with the debug and trace API methods enabled.
This method is available for post-Nitro blocks only (block 22,207,815 and later). For pre-Nitro blocks, use [`arbtrace_block`](/reference/arbitrum-arbtrace-block) instead.
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## Parameters
* `hash` — the hash of the block to be traced.
* `tracer` — an object identifying the type of tracer and its configuration:
* `4byteTracer` — tracer that captures the function signatures and call data sizes for all functions executed during a transaction, creating a map that links each selector and size combination to the number of times it occurred.
* `callTracer` — tracer that captures information on all call frames executed during a transaction. The resulting nested list of call frames is organized into a tree structure that reflects the way the EVM works and can be used for debugging and analysis purposes.
* `prestateTracer` — tracer with two modes: `prestate` and `diff`, where the former returns the accounts needed to execute a transaction, and the latter returns the differences between the pre and post-states of the transaction.
## Response types
### `4byteTracer` response
* `object` — the `4byteTracer` traces object:
* `result` — a map of the function signature, the call data size, and how many times the function was called.
### `callTracer` response
* `object` — the `callTracer` traces object:
* `from` — the address of the sender who initiated the transaction.
* `gas` — the units of gas included in the transaction by the sender.
* `gasUsed` — the total used gas by the call, encoded as hexadecimal.
* `to` — the address of the recipient of the transaction if it was a transaction to an address. For contract creation transactions, this field is `null`.
* `input` — the optional input data sent with the transaction.
* `output` — the return value of the call, encoded as a hexadecimal string.
* `error` — an error message in case the execution failed.
* `revertReason` — the reason why the transaction was reverted, returned by the smart contract if any.
* `calls` — a list of sub-calls made by the contract during the call, each represented as a nested call frame object.
### `prestateTracer` response
* `object` — the `prestateTracer` traces object:
* `smart contract address` — the address of the smart contract associated with the result.
* `balance` — the balance of the contract, expressed in Wei and encoded as a hexadecimal string.
* `code` — the bytecode of the contract, encoded as a hexadecimal string.
* `nonce` — the nonce of the account associated with the contract, represented as an unsigned integer.
* `storage` — a map of key-value pairs representing the storage slots of the contract.
## `debug_traceBlockByHash` code examples
```javascript ethers.js theme={"system"}
const ethers = require('ethers');
const NODE_URL = "YOUR_CHAINSTACK_ENDPOINT";
const provider = new ethers.JsonRpcProvider(NODE_URL);
const traceBlockByHash = async (blockHash) => {
const tracer = { tracer: "callTracer" };
const traces = await provider.send("debug_traceBlockByHash", [blockHash, tracer]);
console.log(traces);
};
traceBlockByHash("0xb3a662bef958318d25b80ba2ce6932d7e2f10262086247fa848f2d96de75fa18");
```
```python web3.py theme={"system"}
from web3 import Web3
node_url = "YOUR_CHAINSTACK_ENDPOINT"
web3 = Web3(Web3.HTTPProvider(node_url))
block_hash = "0xb3a662bef958318d25b80ba2ce6932d7e2f10262086247fa848f2d96de75fa18"
tracer = {"tracer": "callTracer"}
block_traces = web3.provider.make_request('debug_traceBlockByHash', [block_hash, tracer])
print(block_traces)
```
## Use case
The `debug_traceBlockByHash` method is useful for auditing all transactions in a specific block. Developers can use it to analyze gas consumption patterns, identify function call frequencies using the `4byteTracer`, or inspect the full call tree of every transaction in a block using the `callTracer`.
## OpenAPI
````yaml /openapi/arbitrum_node_api/debug_and_trace/debug_traceBlockByHash.json POST /66f812de2a6724a75a51f60dd6f2a154
openapi: 3.0.0
info:
title: Chainstack Node API
version: 1.0.6
description: >-
This is an API for interacting with a Chainstack node using the
debug_traceBlockByHash method.
servers:
- url: https://nd-954-882-037.p2pify.com
security: []
paths:
/66f812de2a6724a75a51f60dd6f2a154:
post:
tags:
- upload
summary: debug_traceBlockByHash
operationId: arbitrumTraceBlockByHash
requestBody:
required: true
content:
application/json:
schema:
type: object
properties:
id:
type: integer
default: 1
jsonrpc:
type: string
default: '2.0'
method:
type: string
default: debug_traceBlockByHash
params:
type: array
items:
anyOf:
- type: string
title: Block Hash
description: The block hash.
- type: object
title: Tracer type
properties:
tracer:
type: string
description: The type of tracer.
default:
- >-
0xb3a662bef958318d25b80ba2ce6932d7e2f10262086247fa848f2d96de75fa18
- tracer: callTracer
responses:
'200':
description: The block traces.
content:
application/json:
schema:
type: object
properties:
jsonrpc:
type: string
id:
type: integer
result:
type: object
````