> ## Documentation Index
> Fetch the complete documentation index at: https://trigger-v3-fix-additional-files.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# io.backgroundPoll()

> `io.backgroundPoll()` allows you to fetch data from a URL on an interval.

## Parameters

<Snippet file="stable-key-param.mdx" />

<ResponseField name="url" type="string" required>
  The url to fetch.
</ResponseField>

<ResponseField name="interval" type="number" required>
  The interval in seconds to wait between requests. Minimum interval is 10 seconds and maximum is 5
  minutes.
</ResponseField>

<ResponseField name="timeout" type="number" required>
  The timeout in seconds before aborting the polling. Minimum timeout is 30 seconds and maximum is 1
  hour.
</ResponseField>

<ResponseField name="requestInit" type="RequestInit">
  Options for the fetch request

  <Expandable title="options" defaultOpen>
    <ResponseField name="method" type="string">
      The HTTP method to use for the request.
    </ResponseField>

    <ResponseField name="headers" type="object">
      Any headers to send with the request. Note that you can use [redactString](sdk/redactString) to
      prevent sensitive information from being stored (e.g. in the logs), like API keys and tokens.
    </ResponseField>

    <ResponseField name="body" type="string | ArrayBuffer">
      The body of the request.
    </ResponseField>
  </Expandable>
</ResponseField>

<ResponseField name="responseFilter" type="ResponseFilter">
  Allows you to filter the response to determine when to stop polling.

  <Expandable title="options" defaultOpen>
    <ResponseField name="status" type="string[]">
      An array of status codes to match against.
    </ResponseField>

    <ResponseField name="headers" type="EventFilter">
      An object of header key/values to match. This uses the [EventFilter matching syntax](/documentation/guides/event-filter)

      ```ts example.ts
      filter: {
        header: {
          "content-type": [{ $startsWith: "application/json" }],
        },
      },
      ```
    </ResponseField>

    <ResponseField name="body" type="EventFilter">
      An [EventFilter](/documentation/guides/event-filter) object to match against the response body. This will only be applied if the response body is JSON.
    </ResponseField>
  </Expandable>
</ResponseField>

<ResponseField name="requestTimeout" type="object">
  An optional object to specify a timeout for each individual request.

  <Expandable title="options" defaultOpen>
    <ResponseField name="durationInMs" type="number" required>
      The timeout in milliseconds before aborting the request.
    </ResponseField>

    <ResponseField name="retry" type="RetryOptions">
      <Expandable title="options">
        {" "}

        <ResponseField name="limit" type="number">
          The maximum number of times to retry the request.
        </ResponseField>

        <ResponseField name="minTimeoutInMs" type="number">
          The minimum amount of time to wait before retrying the request.
        </ResponseField>

        <ResponseField name="maxTimeoutInMs" type="number">
          The maximum amount of time to wait before retrying the request.
        </ResponseField>

        <ResponseField name="factor" type="number">
          The exponential factor to use when calculating the next retry time.
        </ResponseField>

        <ResponseField name="randomize" type="boolean">
          Whether to randomize the retry time.
        </ResponseField>
      </Expandable>
    </ResponseField>
  </Expandable>
</ResponseField>

## Returns

A `Promise` that resolves with the JSON response body of the matching background fetch request. You can specify the type of the response body as a generic parameter.

<RequestExample>
  ```ts polling
  client.defineJob({
    id: "background-poll-job",
    name: "Background Poll Job",
    version: "0.0.1",
    trigger: invokeTrigger({
      schema: z.object({ url: z.string().url() }),
    }),
    run: async (payload, io, ctx) => {
      const result = await io.backgroundPoll<{ foo: string }>("poll", {
        url: payload.url,
        interval: 10, // every 10 seconds
        timeout: 300, // stop polling after 5 minutes
        responseFilter: {
          // stop polling once this filter matches
          status: [200],
          body: {
            status: ["SUCCESS"],
          },
        },
      });
    },
  });
  ```
</RequestExample>