> ## 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.

# trace_replayBlockTransactions | Base

Base API method `trace_replayBlockTransactions` replays transactions in a specified block individually, returning the trace data for each transaction. This method is invaluable for developers, auditors, and analysts who wish to inspect the execution path of transactions within a block, including calls to other contracts, state changes, and execution outcomes without affecting the live blockchain.

## Parameters

* `blockHash` or `blockNumber` — The hash or number of the block whose transactions you want to replay. This can be specified as a hexadecimal string for the block hash or a hexadecimal or decimal number for the block number.
* `traceTypes` — An array of strings specifying the types of traces to return for each transaction. Common trace types include `"vmTrace"`, `"trace"`, and `"stateDiff"`.

## Response

* `result` — An array containing the trace data for each transaction in the specified block. Each item in the array represents the trace of a single transaction, detailing calls to contracts, value transfers, and other relevant state changes that occurred during its execution.

## Use case

The `trace_replayBlockTransactions` method is particularly useful for conducting detailed analyses of block transactions. Developers can use it to debug contract interactions within a specific block, auditors can use it to verify the correctness and security of transactions, and analysts might use it to study transaction patterns or detect anomalies. This method provides a granular view of transaction execution, which is essential for understanding complex interactions on the blockchain.


## OpenAPI

````yaml /openapi/base_node_api/trace_replayBlockTransactions.json POST /2fc1de7f08c0465f6a28e3c355e0cb14
openapi: 3.0.0
info:
  title: trace_replayBlockTransactions
  description: >-
    Replays transactions in a block individually, returning the trace data for
    each transaction.
  version: '1.0'
servers:
  - url: https://base-mainnet.core.chainstack.com
security: []
paths:
  /2fc1de7f08c0465f6a28e3c355e0cb14:
    post:
      tags:
        - Blockchain
      summary: Replay transactions in a block
      operationId: trace_replayBlockTransactions
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                jsonrpc:
                  type: string
                  default: '2.0'
                  example: '2.0'
                method:
                  type: string
                  default: trace_replayBlockTransactions
                  example: trace_replayBlockTransactions
                params:
                  type: array
                  default:
                    - '0xbb623d'
                    - - trace
                  example:
                    - '0xbb623d'
                    - - trace
                id:
                  type: integer
                  default: 1
                  example: 1
      responses:
        '200':
          description: Trace data for transactions in the specified block
          content:
            application/json:
              schema:
                type: object
                properties:
                  jsonrpc:
                    type: string
                  id:
                    type: integer
                  result:
                    type: array
                    items:
                      type: object
                      description: Trace data for a single transaction.

````