The Complete Guide on How to Summarize PDF with LangChain

Last updated on May 19, 2023

Summary :

No need to read through the whole PDF file, LangChain helps you quickly get hold of it and summarize the PDF within several seconds.

Content Table

How to Summarize PDF with LangChain

How to Summarize PDF with LangChain

Have you noticed that all of a sudden we are surrounded by OpenAI products, like ChatGPT? What’s more, it is now widely applied in PDF editors such as PDFgear chatbot, allowing people to chat with the PDF, and also improve business and education efficiency by summarizing the PDFs fast.

ChatGPT does have many feats but because it doesn’t have an official API and needs to manually obtain and regularly change tokens, there might be some inconvenience. In this post, we want to introduce LangChain which can replicate ChatGPT to summarize the PDF files easily. Let’s move on.

How to Summarize PDF with LangChain: Step by Step

LangChain is highly recommended when a longer PDF is in your hand. It helps you fast start a chat with the PDF. Below is detailed guidance on how to summarize PDF with LangChain. If you are interested in it, go ahead.

Step 1. Import the necessary library and modules. Here we use PyPDFLoader to load the PDF file.

Load File in PyPDFLoader

Load File in PyPDFLoader

Step 2. Define the summarize_pdf function to make a summarization. This function defines the PDF file path and an optional custom prompt as input.

Define the Summarize PDF Function

Define the Summarize PDF Function

Step 3. Here we need to set the Gradio Interface. As below, the main function includes the interface of the Gradio and the input and output elements needed in the interface, and more.

Set the Gradio Interface

Set the Gradio Interface

Step 4. Launch the all commands to run the app. For the full source code, you can get it here.

Summarize PDFs with LangChain

Summarize PDFs with LangChain

How to Summarize PDF Using LangChain Alternative

You might have found that to summarize a PDF with LangChain, you need to be familiar with basic Python. It is relatively hard for a newbie. In this part, we have PDFgear Chatbot. It integrates ChatGPT and allows you to use it even when you are offline (PDFgear has a desktop version). No need to input any SQL commands, you can summarize the large PDF with only one click. What’s more, no charge.

Step 1. Download PDFgear and launch it on your device. Both Windows and MacOS are supported.

Step 2. Import the PDF you are going to summarize into PDFgear by tapping on the Open File button.

Import PDFs into PDFgear

Import PDFs into PDFgear

Step 3. Once the PDF is uploaded successfully, you will notice that a chat panel appears on the right. Read through the chats listed on the panel, you will also find that the PDFgear chatbot has automatically listed some questions you potentially will ask. Of course, you can ask your own questions by entering them in the chat window and sending them, and thus you will get your answers based on the content of the PDF.

Here you can get your summarization of the PDF by entering the question, like the summarization of this PDF.

Summarize PDFs with PDFgear Chatbot

Summarize PDFs with PDFgear Chatbot

Apart from PDFgear Chatbot, there are many other AI assistants to help you fast summarize PDF files. And each of them has its own features, know more The 7 Best AI Summarizers.

What is LangChain and Why it Can be Used in PDF Works

To put it simply, LangChain is a framework built around LLMs for developing applications. It can be used for chatbot and summarization. LangChain supports many modules, such as Prompts, Memory, Indexes, Chains, Agents, and Callback.

The use case of PDF is one of the most common use cases LangChain supports, owing to Lang Chain’s Indexes module. It can quickly learn from the context of PDF and generate accurate answers based on the analysis of the whole PDF.


What are the benefits of using language models for PDF summarization?

When there are large amounts of articles or PDFs to summarize, much time and energy are needed to read through all of them. While Large language models now can perform many functions by one system and are equipped with the ability to comprehend human language, increasingly improve efficiency.

Furthermore, it provides a conversational user experience. For example, the use case of

Chatbot improves internal communication in PDF files.

Which language models are best suited for summarizing PDFs?

When it comes to language models, there are two major models. One is Statistical models and the other one is neural models. As the name suggests, Statistical models concentrate on statistics. Instead, neural models tend to mimic the neural networks in the human brain.

In light of their features, Statistical models are more favored when summarizing PDFs.

Can I chat with PDF using LangChain?

Of course, you can. To start it, you need to pre-install the required Python libraries. For detailed guidance on how to achieve it, you can refer to this blog.

How do you summarize a PDF using AI?

Summarizing a PDF using AI has become a common case in daily life. It has greatly saved time and increased working efficiency. Thus, choosing a good AI summarizer can rescue you from the heavy work. Take a look at How to Summarize an Article Using AI Assistant.

Can I summarize a PDF easily without coding skills?

Yes. Most of us are not familiar with basic Python and don’t have any coding skills. No worry, here Top 12 PDF Summarizing Tool with AI are introduced for you to quickly summarize your PDFs.


LangChain has played an important role in our life and is widely used in many fields besides PDF files. With it, you do not need to spend amounts of time reading, and saves you lots of time. Rather than getting a summarization of a PDF, you can also freely chat with it and have a positive interaction.