[GUI Plugin] OPF Helper

[Comfy.n]

OPF Helper is a comprehensive toolkit for inspecting, validating, and managing OPF files in your EPUB library. It offers advanced search, export, and troubleshooting features to help you maintain clean, standards-compliant metadata and structure in your Calibre collection.

OPF Helper began as a simple OPF viewer, but quickly grew to include validation, batch search, and export tools for power users and ebook maintainers.

The plugin provides a streamlined interface with basic (limited) keyboard shortcut support and is organized around several core features:

Show OPF Content
Instantly view the OPF file for any selected book(s)
Syntax highlighting and easy copy/export options
Find Multiple OPF Files

Scan your library for books with more than one OPF file
Quickly filter and review affected books
Find XML Parsing Issues

Detect and report XML errors in OPF files across your library
Helps identify and fix problematic metadata
Export Selected OPFs

Export OPF files from selected books to a chosen folder
Useful for backup, sharing, or external editing
EPUB Version Finder

Locate and mark books by EPUB version (3.0, 2.0, or non-3.0)
Supports targeted maintenance and conversion workflows

Compatibility
Calibre 6.25 or later
Works on Windows, macOS, and Linux (tested on Windows; feedback for other platforms welcome)

License
This plugin is licensed under the GNU GPL v3

Hope you enjoy it!

Release notes

Spoiler:

version 1.0.2
Initial implementation of OPF Standards comparison

version 1.0.1
Debug output now fully suppressed unless explicitly enabled

[Comfy.n]

reserved

[JSWolf]

Why do we have a thread for a non-existent plugin?

[BeckyEbook]

Shhh... It's definitely going to be a surprise.
I understand the situation perfectly. The plugin was almost ready, but just before publication, it turned out that there was a bug that needed to be fixed. Regular forum users cannot delete threads or posts, so let's just wait patiently.

[Comfy.n]

Originally Posted by BeckyEbook

Shhh... It's definitely going to be a surprise.
I understand the situation perfectly. The plugin was almost ready, but just before publication, it turned out that there was a bug that needed to be fixed. Regular forum users cannot delete threads or posts, so let's just wait patiently.

Originally Posted by JSWolf

Why do we have a thread for a non-existent plugin?

hahaha

I think it will take some time for me to make my mind up about the first official release.

I needed the thread URL!