OCR April 21, 2026 · 9 min read

Best Free OCR APIs Compared: Google Vision, Tesseract & AWS Textract

Compare the top OCR APIs for developers — Google Cloud Vision, AWS Textract, Azure AI, and Tesseract — with pricing, accuracy, and code examples.

AltoUnlockPDF Team

PDF Tools Expert

If you’re building an application that processes documents, you’ll need an OCR API. The choice between cloud APIs and self-hosted solutions has significant implications for cost, accuracy, privacy, and latency. Here’s a comprehensive comparison.

The Contenders

API	Provider	Type	Free Tier	Pricing
Cloud Vision API	Google	Cloud	1,000 units/month	$1.50/1,000
Textract	AWS	Cloud	1,000 pages/month	$1.50/1,000
Azure AI Vision	Microsoft	Cloud	5,000 units/month	$1.00/1,000
Tesseract	Open Source	Self-hosted	Unlimited	Free
EasyOCR	Open Source	Self-hosted	Unlimited	Free
AltoUnlockPDF API	Us	Cloud	100/month	Contact us

1. Google Cloud Vision API

Google Cloud Vision is the most widely used cloud OCR API due to Google’s massive training data advantage.

Strengths:

Highest accuracy for printed text (99%+)
Excellent handwriting recognition
Best multilingual support (50+ languages)
Document text detection mode for complex layouts
Auto-detects document orientation

Setup:

from google.cloud import vision

client = vision.ImageAnnotatorClient()

def extract_text(image_path):
    with open(image_path, 'rb') as f:
        content = f.read()
    
    image = vision.Image(content=content)
    
    # For documents with complex layout
    response = client.document_text_detection(image=image)
    
    # For simple text
    # response = client.text_detection(image=image)
    
    return response.full_text_annotation.text

text = extract_text('document.jpg')
print(text)

Pricing: 1,000 free units/month. $1.50 per 1,000 units thereafter. A “unit” is one image.

2. AWS Textract

AWS Textract is specifically designed for document processing with a focus on structured data extraction.

Strengths:

Best for forms and tables — explicitly extracts key-value pairs
Integrates with AWS S3, Lambda, SQS for workflows
Synchronous and asynchronous modes
HIPAA compliant — good for healthcare documents

import boto3

textract = boto3.client('textract', region_name='us-east-1')

def extract_form_data(image_bytes):
    response = textract.analyze_document(
        Document={'Bytes': image_bytes},
        FeatureTypes=['FORMS', 'TABLES']
    )
    
    # Extract key-value pairs from forms
    key_map, value_map, block_map = {}, {}, {}
    for block in response['Blocks']:
        block_map[block['Id']] = block
        if block['BlockType'] == 'KEY_VALUE_SET':
            if 'KEY' in block.get('EntityTypes', []):
                key_map[block['Id']] = block
            else:
                value_map[block['Id']] = block
    
    # Build key-value pairs
    kvs = {}
    for key_id, key_block in key_map.items():
        key_text = get_text(key_block, block_map)
        value_id = get_value_id(key_block)
        if value_id and value_id in value_map:
            value_text = get_text(value_map[value_id], block_map)
            kvs[key_text] = value_text
    
    return kvs

Pricing: 1,000 pages free for first 3 months. $1.50/1,000 pages for text detection; $15/1,000 pages for table/form analysis.

3. Azure AI Vision (Read API)

Microsoft’s Azure AI Vision has strong document understanding capabilities.

Strengths:

Best free tier (5,000 units/month free)
Excellent integration with Microsoft 365 ecosystem
Good performance on handwriting
Preview layout analysis model

from azure.ai.vision.imageanalysis import ImageAnalysisClient
from azure.core.credentials import AzureKeyCredential

client = ImageAnalysisClient(
    endpoint=os.environ['AZURE_VISION_ENDPOINT'],
    credential=AzureKeyCredential(os.environ['AZURE_VISION_KEY'])
)

with open('document.jpg', 'rb') as f:
    result = client.analyze(
        image_data=f.read(),
        visual_features=['READ']
    )

for line in result.read.blocks[0].lines:
    print(line.text)

Pricing: 5,000 free transactions/month. $1.00/1,000 transactions.

4. Tesseract (Self-Hosted — Free Forever)

For privacy-sensitive or high-volume scenarios, Tesseract runs entirely on your server:

import pytesseract
from PIL import Image

def tesseract_ocr(image_path, lang='eng', config='--oem 3 --psm 3'):
    """OCR with Tesseract — completely local, free."""
    image = Image.open(image_path)
    text = pytesseract.image_to_string(image, lang=lang, config=config)
    return text

# High-quality output with bounding boxes
data = pytesseract.image_to_data(
    Image.open('document.jpg'),
    output_type=pytesseract.Output.DICT
)

Pros: Free, private, no internet required, 100+ languages
Cons: Lower accuracy than cloud APIs, requires preprocessing for best results

5. EasyOCR (Modern, Self-Hosted)

EasyOCR is a newer Python library with better accuracy than Tesseract on many document types:

import easyocr

reader = easyocr.Reader(['en', 'fr'])  # Multi-language
results = reader.readtext('document.jpg')

for (bbox, text, confidence) in results:
    print(f"Text: {text}, Confidence: {confidence:.2f}")

pip install easyocr

Pros: Better accuracy than Tesseract, especially for unusual fonts; supports 80+ languages
Cons: Heavier (~1GB models), GPU recommended for speed