JSON Schema

Top-Level Structure

The --format json output uses a flat kids array:

{
  "file name": "document.pdf",
  "number of pages": 12,
  "author": "string | null",
  "title": "string | null",
  "creation date": "string | null",
  "modification date": "string | null",
  "kids": [Element]
}

Element Object

Each element in kids has a type field identifying its kind:

Field	Type	Description
type	string	"heading", "paragraph", "table", "list", "image", "caption", "header", "footer"
id	int	Globally unique sequential ID
page number	int	1-based page index
bounding box	[left, bottom, right, top]	Coordinates in PDF points
content	string	Extracted text (present on paragraph, heading, caption, list item; absent on table, image, list, header, footer)
font	string	Font name (text elements only)
font size	float	Font size in points (text elements only)

Heading-Specific Fields

Field	Type	Description
level	string	Semantic label: "Title", "Subtitle", "Heading1", "Heading2", "Heading3", "Heading4"
heading level	int	Numeric heading level (1–6)

Table-Specific Fields

Field	Type	Description
rows	Row[]	Array of row objects

Row Object

Field	Type	Description
row number	int	0-based row index
cells	Cell[]	Array of cell objects

Cell Object

Field	Type	Description
type	string	Always "table cell"
row number	int	1-based row index
column number	int	1-based column index
row span	int	Number of rows spanned (default: 1)
column span	int	Number of columns spanned (default: 1)
kids	Element[]	Nested child elements (typically empty)

Full Example

{
  "file name": "report.pdf",
  "number of pages": 1,
  "author": null,
  "title": "Quarterly Report",
  "creation date": "2024-01-15",
  "modification date": null,
  "kids": [
    {
      "type": "heading",
      "id": 1,
      "level": "title",
      "heading level": 1,
      "page number": 1,
      "bounding box": [72, 90, 540, 120],
      "font": "Helvetica-Bold",
      "font size": 24.0,
      "content": "Quarterly Report"
    },
    {
      "type": "paragraph",
      "id": 2,
      "page number": 1,
      "bounding box": [72, 140, 540, 200],
      "content": "Revenue grew 23% year-over-year."
    }
  ]
}