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Convert HTML to PDF with Python: A Complete Guide to Using the FileSlap API

Convert HTML to PDF with Python: A Complete Guide to Using the FileSlap API

Transform your HTML content into professional PDFs using Python and our powerful API

July 10, 2025

Why Convert HTML to PDF with Python?

Python developers often need to generate PDFs from HTML content for:

Report generation - Create automated business reports
Invoice creation - Generate professional invoices from templates
Documentation - Convert web content to printable formats
Email attachments - Send formatted documents via email
Data visualization - Turn charts and graphs into shareable PDFs

While there are local Python libraries like weasyprint or pdfkit, they come with installation headaches, dependency issues, and inconsistent rendering across different systems. That's where the FileSlap API comes in - a cloud-based solution that handles all the complexity for you.

Getting Started with FileSlap API

1. Get Your API Key

First, sign up at fileslap.com and grab your API key. It's free to start with 50 conversions per month.

2. Install Required Libraries

pip install requests

That's it! No complex PDF libraries or system dependencies to worry about.

Basic HTML to PDF Conversion

Here's the simplest way to convert HTML to PDF:

import requests

def convert_html_to_pdf(html_content, api_key):
    url = "https://api.fileslap.com/api/convert"
    
    headers = {
        "X-API-KEY": api_key,
        "Content-Type": "application/json"
    }
    
    data = {
        "html": html_content
    }
    
    response = requests.post(url, headers=headers, json=data)
    
    if response.status_code == 200:
        # Save the PDF
        with open("output.pdf", "wb") as f:
            f.write(response.content)
        print("PDF created successfully!")
    else:
        print(f"Error: {response.status_code}")
        print(response.text)

# Example usage
html_content = """
<!DOCTYPE html>
<html>
<head>
    <title>Sample Document</title>
    <style>
        body { font-family: Arial, sans-serif; margin: 40px; }
        h1 { color: #333; }
    </style>
</head>
<body>
    <h1>Hello from Python!</h1>
    <p>This HTML was converted to PDF using the FileSlap API.</p>
</body>
</html>
"""

api_key = "your_api_key_here"
convert_html_to_pdf(html_content, api_key)

Advanced Usage

Error Handling and Retries

import time
from requests.exceptions import RequestException

def convert_with_retry(html_content, api_key, max_retries=3):
    for attempt in range(max_retries):
        try:
            response = convert_html_to_pdf(html_content, api_key)
            
            if response.status_code == 200:
                return response
            elif response.status_code == 429:  # Rate limit
                wait_time = 2 ** attempt
                print(f"Rate limited. Waiting {wait_time} seconds...")
                time.sleep(wait_time)
            else:
                print(f"Error {response.status_code}: {response.text}")
                return None
                
        except RequestException as e:
            print(f"Request failed: {e}")
            if attempt == max_retries - 1:
                raise
    
    return None

Validate HTML Content

def validate_html(html_content):
    """Basic HTML validation"""
    required_tags = ['<html>', '<head>', '<body>']
    html_lower = html_content.lower()
    
    for tag in required_tags:
        if tag not in html_lower:
            return False
    
    return True

def safe_convert(html_content, api_key):
    if not validate_html(html_content):
        raise ValueError("Invalid HTML content")
    
    return convert_html_to_pdf(html_content, api_key)

Real-World Examples

1. Invoice Generator

import datetime

def generate_invoice(customer_name, items, total, api_key):
    html_content = f"""
    <!DOCTYPE html>
    <html>
    <head>
        <title>Invoice</title>
        <style>
            body {{ font-family: Arial, sans-serif; margin: 40px; }}
            .header {{ text-align: center; border-bottom: 2px solid #333; padding-bottom: 20px; }}
            .invoice-details {{ margin: 30px 0; }}
            .items-table {{ width: 100%; border-collapse: collapse; margin: 20px 0; }}
            .items-table th, .items-table td {{ border: 1px solid #ddd; padding: 8px; text-align: left; }}
            .total {{ font-weight: bold; font-size: 18px; text-align: right; }}
        </style>
    </head>
    <body>
        <div class="header">
            <h1>INVOICE</h1>
            <p>Date: {datetime.datetime.now().strftime('%Y-%m-%d')}</p>
        </div>
        
        <div class="invoice-details">
            <h3>Bill To:</h3>
            <p>{customer_name}</p>
        </div>
        
        <table class="items-table">
            <thead>
                <tr>
                    <th>Item</th>
                    <th>Quantity</th>
                    <th>Price</th>
                    <th>Total</th>
                </tr>
            </thead>
            <tbody>
                {''.join([f'<tr><td>{item["name"]}</td><td>{item["quantity"]}</td><td>${item["price"]}</td><td>${item["quantity"] * item["price"]}</td></tr>' for item in items])}
            </tbody>
        </table>
        
        <div class="total">
            <p>Total: ${total}</p>
        </div>
    </body>
    </html>
    """
    
    return convert_html_to_pdf(html_content, api_key)

# Usage
items = [
    {"name": "Web Development", "quantity": 1, "price": 1500},
    {"name": "Hosting Setup", "quantity": 1, "price": 200}
]
generate_invoice("John Doe", items, 1700, "your_api_key")

2. Report Generator with Charts

import datetime

def generate_report(data, api_key):
    # Create a simple chart using HTML/CSS
    chart_html = ""
    for item in data:
        percentage = (item['value'] / max([d['value'] for d in data])) * 100
        chart_html += f"""
        <div style="margin: 10px 0;">
            <div style="display: flex; justify-content: space-between;">
                <span>{item['label']}</span>
                <span>{item['value']}</span>
            </div>
            <div style="background: #f0f0f0; height: 20px; border-radius: 10px;">
                <div style="background: #007bff; height: 100%; width: {percentage}%; border-radius: 10px;"></div>
            </div>
        </div>
        """
    
    html_content = f"""
    <!DOCTYPE html>
    <html>
    <head>
        <title>Monthly Report</title>
        <style>
            body {{ font-family: Arial, sans-serif; margin: 40px; }}
            .header {{ text-align: center; margin-bottom: 30px; }}
            .chart {{ margin: 20px 0; }}
        </style>
    </head>
    <body>
        <div class="header">
            <h1>Monthly Sales Report</h1>
            <p>Generated on {datetime.datetime.now().strftime('%Y-%m-%d')}</p>
        </div>
        
        <div class="chart">
            <h2>Sales Performance</h2>
            {chart_html}
        </div>
    </body>
    </html>
    """
    
    return convert_html_to_pdf(html_content, api_key)

# Usage
data = [
    {"label": "Product A", "value": 1500},
    {"label": "Product B", "value": 2200},
    {"label": "Product C", "value": 800}
]
generate_report(data, "your_api_key")

Performance Tips

Batch Processing: Convert multiple documents in parallel
Caching: Store frequently used templates
Async Processing: Use aiohttp for non-blocking requests
Template Engines: Use Jinja2 for dynamic content

import asyncio
import aiohttp
from jinja2 import Template

async def batch_convert(templates, api_key):
    async with aiohttp.ClientSession() as session:
        tasks = []
        for template in templates:
            task = convert_async(session, template, api_key)
            tasks.append(task)
        
        results = await asyncio.gather(*tasks)
        return results

async def convert_async(session, html_content, api_key):
    url = "https://api.fileslap.com/api/convert"
    headers = {
        "X-API-KEY": api_key,
        "Content-Type": "application/json"
    }
    data = {"html": html_content}
    
    async with session.post(url, headers=headers, json=data) as response:
        return await response.read()

Integration with Popular Frameworks

Flask Integration

from flask import Flask, request, send_file
import io

app = Flask(__name__)

@app.route('/generate-pdf', methods=['POST'])
def generate_pdf():
    html_content = request.json.get('html')
    api_key = "your_api_key"
    
    response = convert_html_to_pdf(html_content, api_key)
    
    if response and response.status_code == 200:
        pdf_io = io.BytesIO(response.content)
        pdf_io.seek(0)
        return send_file(pdf_io, mimetype='application/pdf')
    else:
        return {"error": "PDF generation failed"}, 400

Django Integration

from django.http import HttpResponse
from django.views.decorators.csrf import csrf_exempt
import json

@csrf_exempt
def generate_pdf_view(request):
    if request.method == 'POST':
        data = json.loads(request.body)
        html_content = data.get('html')
        api_key = "your_api_key"
        
        response = convert_html_to_pdf(html_content, api_key)
        
        if response and response.status_code == 200:
            return HttpResponse(response.content, content_type='application/pdf')
        else:
            return HttpResponse("PDF generation failed", status=400)

Get Started Today

Ready to simplify your PDF generation?

Sign up at fileslap.com
Get your API key from the dashboard
Start converting HTML to PDF with just a few lines of Python code

No more wrestling with local PDF libraries or dealing with system dependencies. The FileSlap API handles all the complexity while you focus on building great applications.

Need help? Check out our documentation or reach out to our support team.

Tags: #Python #PDF #API #HTML #Automation #WebDevelopment #FileSlap