> For the complete documentation index, see [llms.txt](https://docs.flowiseai.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.flowiseai.com/integrations/langchain/document-loaders/epub-file.md).

# Epub File

EPUB (Electronic Publication) is a free and open e-book standard by the International Digital Publishing Forum (IDPF). This module provides functionality to load and process EPUB files within your workflow.

This module provides a sophisticated EPUB document loader that can:

* Load single or multiple EPUB files
* Support both base64-encoded files and files from storage
* Extract content per chapter or per file
* Process content with text splitters
* Handle metadata extraction
* Manage temporary file processing

## Inputs

### Required Parameters

* **EPUB File**: The EPUB file(s) to process (.epub extension required)
* **Usage**: Choose between:
  * One document per chapter: Split content by chapters
  * One document per file: Process entire file as one document

### Optional Parameters

* **Text Splitter**: A text splitter to process the extracted content
* **Additional Metadata**: JSON object with additional metadata
* **Omit Metadata Keys**: Comma-separated list of metadata keys to omit

## Outputs

* **Document**: Array of document objects containing metadata and pageContent
* **Text**: Concatenated string from pageContent of documents

## Features

* Multiple file processing
* Chapter-level splitting
* File-level processing
* Storage integration
* Metadata customization
* Text splitting support
* Temporary file handling
* Error handling

## Processing Modes

### Per Chapter Mode

* Creates separate documents for each chapter
* Maintains chapter structure
* Preserves chapter metadata
* Better for detailed analysis

### Per File Mode

* Processes entire file as one document
* Maintains overall structure
* Simpler document organization
* Better for overview analysis

## Notes

* Supports both local and storage-based files
* Handles base64 encoded content
* Automatically cleans up temporary files
* Preserves document structure
* Supports custom metadata addition
* Error handling for invalid files
* Memory-efficient processing