> ## 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.

<AgentInstructions>

## Submitting Feedback

If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback:

POST https://docs.chainstack.com/feedback

```json
{
  "path": "/reference/base-newpendingtransactionfilter",
  "feedback": "Description of the issue"
}
```

Only submit feedback when you have something specific and actionable to report.

</AgentInstructions>

# eth_newPendingTransactionFilter | Base

Base API method that creates a filter in the node to notify when new pending transactions are received. To check if the state has changed, call eth\_getFilterChanges with the filter ID returned by this method.

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## Parameters

* `none`

## Response

* `result` — a string representing the filter ID. This ID should be used in subsequent calls to eth\_getFilterChanges to retrieve new pending transactions.

## Use case

The `eth_newPendingTransactionFilter` method is useful for applications that need to monitor the mempool for new transactions. Common use cases include:

* Building transaction monitoring tools
* Creating real-time transaction tracking interfaces
* Implementing MEV (Maximal Extractable Value) strategies
* Monitoring specific addresses for pending transactions

Note: After creating the filter, you need to poll `eth_getFilterChanges` periodically to get updates. Filters timeout if they're not used for a period of time, so applications should be prepared to recreate them if necessary.


## OpenAPI

````yaml /openapi/base_node_api/eth_newPendingTransactionFilter.json POST /2fc1de7f08c0465f6a28e3c355e0cb14
openapi: 3.0.0
info:
  title: eth_newPendingTransactionFilter example
  version: 1.0.0
  description: >-
    This is an API example for eth_newPendingTransactionFilter, a method to
    create a new filter object that  notifies when new pending transactions
    enter the transaction pool.
servers:
  - url: https://base-mainnet.core.chainstack.com
security: []
paths:
  /2fc1de7f08c0465f6a28e3c355e0cb14:
    post:
      tags:
        - Ethereum Operations
      summary: eth_newPendingTransactionFilter
      operationId: newPendingTransactionFilter
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                jsonrpc:
                  type: string
                  default: '2.0'
                method:
                  type: string
                  default: eth_newPendingTransactionFilter
                id:
                  type: integer
                  default: 1
      responses:
        '200':
          description: The ID of the created pending transaction filter
          content:
            application/json:
              schema:
                type: object
                properties:
                  jsonrpc:
                    type: string
                  id:
                    type: integer
                  result:
                    type: string

````