EPUBCheck for VS Code
EPUB conformance checker and generator for VS Code, powered by the official W3C EPUBCheck tool.
Validate expanded (unzipped) EPUB projects directly from VS Code, view errors in the Problems panel, and generate .epub files — all without leaving the editor.
Features
- Generate and validate EPUB files from expanded EPUB directories
- Unzip and validate existing
.epub files directly
- Problems panel integration with inline error squiggles
- Status bar indicator showing validation state
- Multiple EPUB support — auto-detects all EPUB projects in your workspace
- Export reports in Markdown, Text, or JSON format
- Context menu — right-click folders or
.epub files in Explorer to run commands
- File browser for selecting
epubcheck.jar and report directory
Requirements
Java Runtime
EPUBCheck requires Java 11 or above. Download from:
EPUBCheck
Download the latest EPUBCheck release:
- Go to EPUBCheck Releases
- Download the ZIP file (e.g.,
epubcheck-5.3.0.zip)
- Extract it to a location on your computer
- Note the path to
epubcheck.jar inside the extracted folder
Setup
After installing the extension:
- Open VS Code Settings (
Cmd+, on macOS / Ctrl+, on Windows/Linux)
- Search for "EPUBCheck"
- Set EPUBCheck: Jar Path to the full path of your
epubcheck.jar file
- Example:
/Users/username/tools/epubcheck-5.3.0/epubcheck.jar
Commands
Open the Command Palette (Cmd+Shift+P / Ctrl+Shift+P) and type "EPUBCheck":
| Command |
Description |
| EPUBCheck: Generate and Validate EPUB |
Validate the EPUB and generate a .epub file |
| EPUBCheck: Generate EPUB Only |
Generate a .epub file without detailed validation |
| EPUBCheck: Generate EPUB and Validation Report |
Validate, generate .epub, and save a report file |
| EPUBCheck: Unzip EPUB and Validate |
Extract .epub files and validate the contents |
| EPUBCheck: Select epubcheck.jar |
Browse for epubcheck.jar using a file picker |
| EPUBCheck: Select Report Directory |
Browse for the report output directory |
You can also right-click on a folder in the Explorer to access the first three commands, or right-click on a .epub file to unzip and validate it.
Settings
| Setting |
Default |
Description |
epubcheck.jarPath |
"" |
Path to epubcheck.jar (required). Use the Browse link in settings. |
epubcheck.javaPath |
"java" |
Path to Java executable |
epubcheck.reportFormat |
"markdown" |
Report format: markdown, text, or json |
epubcheck.reportDirectory |
"" |
Directory to save reports. Empty = workspace root. |
epubcheck.deleteEpubAfterUnzip |
false |
Delete .epub file after extracting |
epubcheck.timeout |
120 |
Timeout in seconds |
epubcheck.showContextMenu |
true |
Show commands in Explorer context menu |
How It Works
- The extension detects EPUB projects by finding directories with a
mimetype file
- When you run a command, it invokes EPUBCheck via Java to validate the expanded EPUB
- Validation results appear in the Problems panel with links to error locations
- The
.epub file is generated in the parent directory of the EPUB project folder
EPUB Project Structure
Your EPUB project directory should look like this:
my-book/
├── mimetype ← Required: contains "application/epub+zip"
├── META-INF/
│ └── container.xml
└── OEBPS/
├── content.opf
├── nav.xhtml
├── chapter1.xhtml
└── style.css
Contributing
Bug reports and feature requests are welcome on GitHub Issues.
This extension was built with Claude Code (Anthropic).
License
MIT
