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

# SenseML

*SenseML* is a query language that lets you extract structured data from documents, for example, from PDFs. A field is the basic SenseML query unit for extracting a piece of document data. The output of a field is a JSON key-value pair that structures the extracted data.

Here's a simple example of a field:

```JSON JSON 
{

  "fields": [
    {
      "id": "name_of_output_key",
      "anchor": "an anchor is some text to match. An anchor can be an array of matches",
      "method": {
        "id": "label",
         "position": "below"
      }
    },
  ]
}
```

The following image shows this example in the Sensible app:

![Click to enlarge](https://mintlify.s3-us-west-1.amazonaws.com/sensible/assets/v0/images/screenshots/basic_field.png)

As the preceding image shows, here's the output of the example field:

```JSON JSON 
{
  "name_of_output_key": {
    "type": "string",
    "value": "Below the matching anchor, this is the data to extract. The anchor is a label for this data."
  }
}
```

This example shows the following key concepts:

| key                                                                     | description                                                                                                                                                                                                                                |
| ----------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| [field](/senseml-reference/field-query-object/index-field-query-object) | A query that extracts data in relationship to matched text. Its ID is the key for the extracted data. In this example, name\_of\_output\_key.                                                                                              |
| **[anchor](/senseml-reference/field-query-object/anchor)**              | Matched text that helps narrow down a location in the document from which to extract data. In this example, "an anchor is some text to match...".                                                                                          |
| [method](/senseml-reference/field-query-object/method)                  | Defines how to expand out from the anchor and extract data. In this example, the Label method extracts data that's below the anchor ("position": "below"). For a list of methods, see [Methods](/senseml-reference/methods/index-methods). |

For a more complete SenseML example, see the [SenseML introduction](/senseml-reference/senseml-reference-introduction).