Extract text, tables, and more from PDFs

This guide explains how to extract data from PDFs using Document Engine.

You can extract the following pieces of information from a PDF document:

Sending the request to extract data

To extract data on all pages of a document, post a multipart request to the /api/build endpoint. In the instructions, specify the following output parameters:

  • type specifies the output type. Set this to json-content.
  • plainText is a Boolean value that determines whether to extract data as plain text.
  • structuredText is a Boolean value that determines whether to extract data as structured text. Enabling this option gives you information about characters, lines, paragraphs, and words.
  • keyValuePairs is a Boolean value that determines whether to extract key-value pairs.
  • tables is a Boolean value that determines whether to extract table data.
  • language specifies the language used for recognizing text with optical character recognition (OCR). Sometimes, text is stored in a PDF or an image in a way that makes it so you cannot search or copy it. Nutrient’s OCR engine allows you to recognize text and save it in a separate file where you can both search and copy and paste the text.
Terminal window
curl -X POST http://localhost:5000/api/build \
  -H "Authorization: Token token=<API token>" \
  -F document=@/path/to/example-document.pdf \
  -F instructions='{
  "parts": [
    {
      "file": "document"
    }
  ],
  "output": {
    "type": "json-content",
    "plainText": true,
    "structuredText": true,
    "keyValuePairs": true,
    "tables": true,
    "language": "english"
  }
}' \
  -o result.json

For more information on the Build instructions, refer to the API Reference.

Interpreting the data extraction response

The API response provides information about the data you included in the API request, such as:

  • Plain text
  • Structured text with information about characters, lines, paragraphs, and words
  • Extracted key-value pairs
  • Tables

Example data extraction response 

{
  "pages": [
    {
      "pageIndex": 0,
      "plainText": "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa.\n",
      "structuredText": {
        "characters": [
          {
            "bbox": {
              "left": 0,
              "top": 0,
              "width": 100,
              "height": 100
            },
            "value": "T"
          }
        ],
        "lines": [
          {
            "bbox": {
              "left": 0,
              "top": 0,
              "width": 100,
              "height": 100
            },
            "firstWordIndex": 0,
            "isRTL": false,
            "isVertical": false,
            "wordCount": 5
          }
        ],
        "paragraphs": [
          {
            "bbox": {
              "left": 0,
              "top": 0,
              "width": 100,
              "height": 100
            },
            "firstLineIndex": 0,
            "lineCount": 3
          }
        ],
        "words": [
          {
            "bbox": {
              "left": 0,
              "top": 0,
              "width": 100,
              "height": 100
            },
            "characterCount": 4,
            "firstCharacterIndex": 0,
            "isFromDictionary": true,
            "value": "word"
          }
        ]
      },
      "keyValuePairs": [
        {
          "confidence": 95.4,
          "key": {
            "bbox": {
              "left": 0,
              "top": 0,
              "width": 100,
              "height": 100
            },
            "content": "#"
          },
          "value": {
            "bbox": {
              "left": 0,
              "top": 0,
              "width": 100,
              "height": 100
            },
            "content": "€",
            "dataType": "Currency"
          }
        }
      ],
      "tables": [
        {
          "confidence": 95.4,
          "bbox": {
            "left": 0,
            "top": 0,
            "width": 100,
            "height": 100
          },
          "cells": [
            {
              "bbox": {
                "left": 0,
                "top": 0,
                "width": 100,
                "height": 100
              },
              "rowIndex": 0,
              "columnIndex": 0,
              "isHeader": true,
              "text": "Invoice number"
            }
          ],
          "columns": [
            {
              "bbox": {
                "left": 0,
                "top": 0,
                "width": 100,
                "height": 100
              }
            }
          ],
          "lines": [
            {
              "bbox": {
                "left": 0,
                "top": 0,
                "width": 100,
                "height": 100
              },
              "isVertical": false,
              "thickness": 0
            }
          ],
          "rows": [
            {
              "bbox": {
                "left": 0,
                "top": 0,
                "width": 100,
                "height": 100
              }
            }
          ]
        }
      ]
    }
  ]
}