> ## Documentation Index
> Fetch the complete documentation index at: https://api.globalwebindex.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Step 2: Filter by Waves

Since you’re interested in the past year, you need to filter the data to include
waves (time periods) that cover this range. For example, you’ll use waves from `Q4 2023` to `Q4 2024`  .

# What is a wave?

A wave represents the time period during which data was collected, such as quarterly
or yearly intervals. Waves allow us to analyze trends over time or focus on specific periods.

To retrieve available waves for the core namespace, use the **Waves Filter Endpoint**. From the responses, you can
identify the waves that cover the past year (`q4_2023`, `q1_2024`, `q2_2024`, `q3_2024`, `q4_2024`).

<RequestExample>
  ```bash theme={null}
  curl -X POST "https://api.globalwebindex.com/v2/waves/filter" \
    -H "Content-Type: application/json" \
    -H "Authorization: Bearer YOUR_API_KEY" \
    -d '{"namespaces": [{"code": "core"}]}'
  ```
</RequestExample>

<ResponseExample>
  ```json Response theme={null}
  {
    "waves": [
       {
        "id": "69",
        "name": "Q4 2023",
        "accessible": true,
        "code": "q4_2023",
        "date_start": "2023-10-01T00:00:00Z",
        "date_end": "2023-12-31T00:00:00Z",
        "kind": "quarter",
        "namespaces": [
          {
            "code": "core"
          }
        ]
      },
      {
        "id": "70",
        "name": "Q1 2024",
        "accessible": true,
        "code": "q1_2024",
        "date_start": "2024-01-01T00:00:00Z",
        "date_end": "2024-03-31T00:00:00Z",
        "kind": "quarter",
        "namespaces": [
          {
            "code": "core"
          }
        ]
      },
      ...
    ]
  }
  ```
</ResponseExample>