Unleashing Innovation: A Deep Dive into LangChain, Document AI, and Beyond

Walter Code
6 min readJun 13, 2024


In our latest workshop, the focus was on artificial intelligence. Our colleague, Sanel Delić, conducted an enlightening session that significantly expanded our knowledge in this dynamic field. Sanel’s expertise and engaging presentation style brought clarity to complex concepts and highlighted the potential of AI in transforming our workflows. Join us as we embark on an exploration of two cutting-edge technologies that are revolutionizing the fields of language processing and document management: LangChain and Document AI.

Introducing LangChain:

LangChain is a pioneering orchestration framework that empowers developers to leverage the capabilities of Large Language Models (LLMs) in their applications. Let us take a closer look at the components that power this innovative framework:

  • Document Loader: LangChain supports a variety of document loaders, providing developers with flexibility in ingesting data from diverse sources. Whether it is Airtable for structured data, CSV files for tabular data, AWS (Amazon Web Services) S3 directories for cloud-based storage, or even Figma for design documents, LangChain’s document loaders streamline the process of ingesting and preprocessing textual data, making it ready for analysis.
  • LLMs: At the core of LangChain’s functionality are Large Language Models, which excel in tasks such as text generation, summarization, and sentiment analysis. These advanced AI models have been pre-trained on vast amounts of textual data and can be fine-tuned for specific applications using LangChain’s framework.
  • Vector Stores: LangChain integrates seamlessly with vector stores such as Azure Cosmos DB, Elastic Search, PG Vector, and Redis. These vector stores provide efficient storage and retrieval of textual information, enabling developers to store and access semantic representations of text for analysis and processing.
  • Chains: Configurations that link multiple components in a sequence, enabling complex workflows and multi-step reasoning.
  • Agents: Systems that use language models to make decisions, execute tasks, and interact with external tools dynamically.
  • Callbacks: Mechanisms for logging, monitoring, and modifying the behavior of various components during runtime to enhance control and debugging.
  • Datasets: Collections of data tailored for training, evaluating, and fine-tuning language models within specific contexts or domains.
  • Tools: Integration capabilities that allow language models to interact with APIs, databases, and other external systems to extend functionality.
  • Prompt Templates: Tools for creating, storing, and managing prompts to standardize and optimize interactions with language models.

Each component plays a vital role in building robust, flexible, and efficient applications that leverage the capabilities of language models.

LangChain’s capabilities and processes provide a powerful way to extract information from all sorts of documents and media. Here is a detailed example of how to ask questions and get answers from PDF files:

  1. PDF Processing: The process starts by processing one or multiple PDF files and extracting the raw text data contained within.
  2. Chunking Text: The extracted text is then broken down into manageable chunks. This step is crucial as it allows for more efficient processing and analysis of the content.
  3. Embeddings: Each chunk of text is converted into embeddings, which are dense vector representations of the text. Embeddings capture the semantic meaning of the text, allowing for more nuanced analysis and comparison.
  4. Vector Store: These embeddings are stored in a vector store, such as Azure Cosmos DB, Elastic Search, PG Vector, or Redis. The vector store allows for efficient retrieval of embeddings based on semantic similarity.
  5. Semantic Search: When a user queries the system, the query is also converted into an embedding. Semantic search techniques are then used to find the most relevant text chunks in the vector store by comparing their embeddings to the query embedding.
  6. Ranked Results: The results from the semantic search are ranked based on their relevance to the query. The highest-ranked results are then used to generate the definitive answer.
  7. Answer Extraction: Based on the ranked results from the semantic search, the system uses the Large Language Model (LLM) to extract or generate the most relevant answer. The LLM processes the context provided by the top-ranked text chunks to generate a coherent and accurate response.

Exploring Document AI:

Document AI is a game-changing technology developed by Google that leverages machine learning algorithms to extract valuable insights from unstructured documents. Let’s delve deeper into its capabilities through an example where we set up a processor to extract information from invoices and use it to streamline our internal invoice management processes:

Process Flows:

Creating a Processor: The first step in harnessing the power of Document AI is creating a processor. This involves choosing the best pre-trained model to be used to extract text from documents. There are general processors, made for generic text extraction, and specialized processors, which have been trained to extract information from specific documents like invoices, bills, or passports.

Uploading Documents: Once the processor is created, we upload documents to the system for processing. Document AI supports various file formats, including PDFs, Word documents, and images. Users can upload individual documents or batch upload large sets of documents for processing.

Editing Schema: Users can edit the schema, or in other words, customize which labels should be used for training and data extraction. This includes renaming fields, adding new fields, or removing unnecessary fields to streamline further processing.

Auto-labeling: Document AI utilizes machine learning algorithms to automatically label documents based on their content. By analyzing the text and context of each document, a well-trained Document AI processor auto-label documents with high accuracy. This automated labeling process saves time and effort, especially when dealing with large volumes of documents.

Manual Labeling: In cases where auto-labeling may not be sufficient, users can and should manually label documents to ensure the most accurate classification. This approach allows users to review and correct the labels assigned by the automated system, improving the overall accuracy of the document classification process.

Model Training: Document AI allows users to retrain and fine-tune the underlying machine learning models based on feedback and additional labeled data. By continuously training the models with new data, users can improve the accuracy and performance of the document processing pipeline over time.

Evaluation and Testing: Once the models are trained, they are evaluated and tested to ensure their accuracy and performance. This involves running test documents through the processing pipeline and comparing the predicted labels against ground truth labels to measure the model’s performance metrics such as precision, recall, and F1-score.

Deployment: Finally, the trained models are deployed into production environments, where they can be used to process large volumes of documents efficiently and accurately. Document AI provides APIs and SDKs for seamless integration with existing systems, allowing developers to incorporate document processing capabilities into their applications with ease.


As we explore the exciting world of LangChain and Document AI, we see how these cutting-edge technologies are transforming the way we handle documents and process language. They’re making tasks like managing document processing easier and more efficient. These solutions are driving innovation and changing the landscape of technology.