PDF.co PDF Merge is the best tool to merge large PDF files into a single PDF. Working with our online PDF merger is absolutely secure. The entire process of merging PDF files happens on the client side (directly in your browser), which means no third parties can access your data. Our PDF merger is completely web-based and can be accessed wherever you are, from any computer. It is compatible with all major browsers and operating systems. Using Python and PDF.co Web API will only take a few seconds to merge PDF files together.
Now, we will show you how to merge large PDF files in Python using PDF.co Web API. We will use 2 large PDF files to merge into a single PDF.
- Install the Request Module
- Open Visual Studio Code Editor
- Setup Python Code
- Run the Program Result
- Merge PDF Output
- PDF.co PDF Merge Demo

Follow this simple step-by-step guide to merge large PDF files into a single PDF.
Step 1: Install the Request Module
- To begin, let’s start by installing the request module to manage new packages written in Python. In your command line, type
python -m pip install request
and click the Enter button to install the request module.
Step 2: Open Visual Studio Code Editor
- After installing the request module, open the Visual Studio Code Editor. You can also use your favorite editor in Python.
- Next, add the Python sample code. You can get the Python sample code at this link.
Step 3: Setup Python Code
Now, let’s set up the Python code.
- Add your PDF.co API Key in line 6. You can get the API Key in your PDF.co dashboard. If you don’t have an account, kindly sign up to PDF.co to get an API Key.
- In lines 12 and 13, input the source PDF file names. You can download the sample PDF files at this link.
- For line 16, enter your desired output file name of the merged PDF files.
After setting up the Python code, save the file and click the Run button to execute the program.
Step 4: Run the Program Result
- Once the program runs successfully, check your Python program folder to view the output.
Step 5: Merge PDF Output
- Here are the large PDF files that we successfully merge into a single PDF
Step 6: PDF.co PDF Merge Demo
- Check out this PDF.co PDF Merge in action.

In this tutorial, you learned how to merge large PDF files using Python. You also learned how to use the PDF.co Web API to merge large PDF files into a single PDF.