PDF OCR - Scanned Document to Text Converter

PDF4me Convert PDF to Editable PDF using OCR enables you to convert image-based PDF documents to fully editable PDFs using OCR technology. This API service processes scanned PDFs and image-based documents, extracting text and making documents searchable and editable. The API receives PDF content and OCR parameters through REST API calls, utilizing Base64 encoding for secure transmission. With support for quality control, intelligent OCR processing, and language specification, this solution is ideal for document digitization and content accessibility workflows.

Authenticating Your API Request

To access the PDF4me REST API, every request must include proper authentication credentials. Authentication ensures secure communication and validates your identity as an authorized user of the REST API.

Get your api Key

Key Features

• OCR Processing: Convert image-based PDFs to fully editable documents with text recognition
• Quality Control: Choose between Draft (1 API call per file) and High (2 API calls per page) quality processing
• Intelligent Processing: Skip OCR when text is already searchable to optimize performance
• Language Support: Specify document language for improved text recognition accuracy
• Base64 Encoding: Secure file content transmission using Base64 encoding
• Simple API Integration: RESTful API designed for automated PDF OCR workflows

REST API Endpoint

The PDF4me REST API uses standard HTTP methods to interact with resources. All OCR-based PDF conversion operations are performed through a single endpoint:

• Method: POST
• Endpoint: /api/v2/ConvertOcrPdf

REST API Parameters

Complete list of parameters for the Convert PDF to editable PDF using OCR REST API. Parameters are organized by category for better understanding and implementation.

Important: Parameters marked with an asterisk (*) are required and must be provided for the API to function correctly.

Required Parameters

Parameter	Type	Description	Example
docContent*	Base64	The content of the input PDF file encoded in Base64 format	JVBERi...
docName*	String	Source PDF file name with .pdf extension	output.pdf
qualityType*	String	OCR quality type: Draft (1 API call per file) for normal PDFs, High (2 API calls per page) for scanned documents	Draft
ocrWhenNeeded*	String	OCR only when needed: true to skip if text is already searchable, false to always perform OCR	true
outputFormat*	String	Output format (must be "true" for standard output)	true
isAsync*	Boolean	Enable asynchronous processing. When true, the API returns a 202 status and provides a polling URL in the Location header	true

Optional Parameters

Parameter	Type	Description	Example
language	String	Language of text in source file (e.g., "English", "Spanish", "French", "German"). Only use if output is not recognizable	English
mergeAllSheets	Boolean	Merge all sheets if applicable	true

Output

The PDF4me Convert PDF to Editable PDF using OCR REST API returns different responses based on the processing mode. The API returns the converted PDF as a Base64-encoded string in JSON format.

Success Response

Synchronous Processing (Default)

When isAsync is false, the API processes the request immediately:

Status Code: 200 OK

Content-Type: application/json

Response Body:

{
  "docName": "output.pdf",
  "docContent": "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"
}

Response Fields:

• docName (string): The output PDF file name
• docContent (string): The converted editable PDF, encoded as Base64 string

How to Use:

1. Extract the docContent field from the JSON response
2. Decode the Base64 string to get the binary PDF data
3. Save or process the PDF file as needed

Example (JavaScript):

const response = await fetch(url, options);
const data = await response.json();
const pdfBytes = atob(data.docContent); // Decode Base64
// Save or process pdfBytes

Asynchronous Processing

Asynchronous Processing

When isAsync: true is set, the API processes the request asynchronously:

Status Code: 202 Accepted

Response Headers:

Location: https://api.pdf4me.com/api/v2/ConvertOcrPdf/poll/12345-abcde-67890

Polling Process:

1. Extract the Location header from the 202 response
2. Poll the URL using GET requests
3. Continue polling until you receive a 200 OK status
4. The final response contains the same JSON format with docName and docContent (Base64)

Polling Example:

// Initial request returns 202 with Location header
const response = await fetch(url, options);
const location = response.headers.get('Location');

// Poll until complete
while (true) {
  const pollResponse = await fetch(location, { headers: { 'Authorization': 'Basic ' + apiKey } });
  if (pollResponse.status === 200) {
    const data = await pollResponse.json();
    // Process data.docContent (Base64 PDF)
    break;
  }
  await new Promise(resolve => setTimeout(resolve, 2000)); // Wait 2 seconds
}

Error Responses

Error Responses

Status Code	Description	Example Response
400 Bad Request	Invalid request parameters or missing required fields	{"error": "Missing required parameter: qualityType"}
401 Unauthorized	Invalid or missing API key	{"error": "Unauthorized"}
500 Internal Server Error	Server error during processing	{"error": "Internal server error"}

Response Format Details

Understanding the JSON Response

The OCR conversion response is a JSON object containing:

• docName: The output PDF file name
• docContent: The converted editable PDF, encoded as Base64 string

Base64 Decoding:

The docContent field contains the PDF file encoded in Base64. Decode it to get the binary PDF data:

const pdfBytes = atob(data.docContent); // JavaScript

import base64
pdf_bytes = base64.b64decode(data['docContent']) # Python

Request Example

Header

Content-Type: application/json
Authorization: Basic YOUR_BASE64_ENCODED_API_KEY

Note: The API key must be Base64 encoded. Get your API key from the PDF4me Dashboard

Payload

{
  "docContent": "JVBERi...",
  "docName": "output.pdf",
  "qualityType": "Draft",
  "ocrWhenNeeded": "true",
  "language": "English",
  "outputFormat": "true",
  "isAsync": true
}

Code Samples

The PDF4me Convert PDF to editable PDF using OCR REST API provides code samples in multiple programming languages. Choose the language that best fits your development environment:

C#

C# (CSharp) Sample

Complete C# implementation for converting PDF to editable PDF using OCR:

View C# Sample

Java

Java Sample

Java implementation with full error handling and response processing:

View Java Sample

JavaScript

JavaScript Sample

Node.js and browser-compatible JavaScript implementation:

View JavaScript Sample

Python

Python Sample

Python implementation with requests library and JSON handling:

View Python Sample

Salesforce

Salesforce Sample

Salesforce Apex implementation for CRM integration:

View Salesforce Sample

n8n

n8n Sample

n8n workflow implementation for automation:

View n8n Sample

Google Script

Google Script Sample

Google Apps Script implementation for Google Workspace integration:

View Google Script Sample

AWS Lambda

AWS Lambda Sample

Serverless AWS Lambda function implementation:

View AWS Lambda Sample

OCR Conversion Features

Text Recognition Processing

• Advanced OCR Engine: Advanced optical character recognition for accurate text extraction
• Quality Options: Draft quality for normal PDFs, High quality for scanned documents
• Intelligent Detection: Automatic detection of searchable vs. image-based content
• Professional Results: High-quality text recognition with accurate character extraction
• Advanced Processing: Support for complex document layouts and formatting

Language Support

• Multi-language Recognition: Support for various languages and character sets
• Language Specification: Optional language parameter for improved accuracy
• Character Recognition: Accurate recognition of different alphabets and symbols
• Professional Processing: High-quality language-specific text recognition
• Flexible Input: Support for documents in multiple languages

Advanced Features

• Smart Processing: Intelligent OCR processing that skips unnecessary operations
• Format Flexibility: Support for various PDF formats and document types
• Professional Conversion: High-quality document conversion with clear text output
• Flexible Options: Customizable processing parameters for specific requirements

Industry Use Cases & Applications

Legal & Professional Services

Legal & Professional Services Use Cases

• Legal Document Processing: Convert scanned legal documents to searchable, editable formats
• Legal Archive Processing: Digitize historical legal documents and archives
• Compliance Documentation: Convert regulatory documents to searchable formats for compliance monitoring
• Legal Document Accessibility: Make legal PDFs accessible for text search and editing

Government & Compliance

Government & Compliance Use Cases

• Archive Processing: Digitize historical documents and archives for digital preservation
• Compliance Documentation: Convert regulatory documents to searchable formats for compliance monitoring
• Public Records: Digitize public records and government documents
• Regulatory Documentation: Convert regulatory documents to editable formats

Education & Research

Education & Research Use Cases

• Academic Research: Digitize research papers and academic documents for text analysis
• Educational Content: Convert scanned educational documents to editable formats
• Research Archive Processing: Digitize historical research documents and archives
• Academic Document Accessibility: Make academic PDFs accessible for text search

Business & Enterprise

Business & Enterprise Use Cases

• Document Digitization: Convert scanned paper documents to editable digital formats
• Business Process Automation: Automate document processing workflows with OCR conversion
• Content Management: Transform image-based content into editable, searchable documents
• Content Accessibility: Make image-based PDFs accessible for screen readers and text search

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