> ## 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.

# eth_createAccessList | Base

Base API method `eth_createAccessList` generates an access list for a transaction based on specific default values. An access list includes addresses and storage keys the transaction intends to access, facilitating more efficient gas usage.

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## Parameters

* `transactionObject` — an object containing transaction parameters with default values:
  * `from` — the address of the sender.
  * `data` — the data being sent with the transaction.
* `blockParameter` — specifies the blockchain state to use for generating the access list, with a default value of `"pending"`.

## Response

* `result` — an object containing:
  * `accessList` — the generated access list, detailing addresses and storage keys the transaction will access.
  * `gasUsed` — the estimated gas used to execute the transaction with the generated access list.

## Use case

The `eth_createAccessList` method is crucial for:

* Preparing transactions that optimize gas usage by explicitly stating which addresses and storage keys will be accessed.
* Developers aiming to reduce transaction costs and improve efficiency on the Base network.
* Transactions that comply with EIP-2930, which introduces access lists as a transaction type to specify state access.

This method provides a practical approach to optimizing transaction execution and gas usage on the Base blockchain by pre-determining the access list.


## OpenAPI

````yaml /openapi/base_node_api/eth_createAccessList.json POST /2fc1de7f08c0465f6a28e3c355e0cb14
openapi: 3.0.0
info:
  title: eth_createAccessList example with default values
  version: 1.0.0
  description: >-
    This is an API example for eth_createAccessList, a method to generate an
    access list for a transaction,  using specific default values.
servers:
  - url: https://base-mainnet.core.chainstack.com
security: []
paths:
  /2fc1de7f08c0465f6a28e3c355e0cb14:
    post:
      tags:
        - Ethereum Operations
      summary: eth_createAccessList
      operationId: createAccessList
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                jsonrpc:
                  type: string
                  default: '2.0'
                method:
                  type: string
                  default: eth_createAccessList
                id:
                  type: integer
                  default: 1
                params:
                  type: array
                  items:
                    anyOf:
                      - type: object
                        properties:
                          from:
                            type: string
                            default: '0xaeA8F8f781326bfE6A7683C2BD48Dd6AA4d3Ba63'
                          data:
                            type: string
                            default: '0x608060806080608155'
                      - type: string
                        default: pending
                  default:
                    - from: '0xaeA8F8f781326bfE6A7683C2BD48Dd6AA4d3Ba63'
                      data: '0x608060806080608155'
                    - pending
      responses:
        '200':
          description: The generated access list and gas used
          content:
            application/json:
              schema:
                type: object
                properties:
                  jsonrpc:
                    type: string
                  id:
                    type: integer
                  result:
                    type: object
                    properties:
                      accessList:
                        type: array
                        items:
                          type: object
                          properties:
                            address:
                              type: string
                            storageKeys:
                              type: array
                              items:
                                type: string
                      gasUsed:
                        type: string

````