How it compares

All five are open source, and each one is good at a different job. The table gives the quick view, and the sections below say who each one suits.

At a glance

	calibre-zen	calibre	Calibre-Web Automated	BookOrbit	Readest
What it is	calibre’s engine, its own UI	Ebook library manager	Web library for a server	Web library and reading hub	Ebook reader
Where it runs	Windows, macOS, Linux, Docker	Windows, macOS, Linux	Docker on a server	Docker on a server	Computers, phones, web
Desktop app	Yes	Yes	No	No	Yes
In a browser	calibre’s web app	calibre’s web app	Yes, its main app	Yes, its main app	Yes, a web app
On a phone	In the browser	In the browser	Browser, unofficial app	iPhone app, Android coming	iPhone and Android
Self-hosting	Docker image	calibre-server	Docker image	Docker with PostgreSQL	Its sync, if you like
Opens a calibre library	Yes, as it is	Yes	Yes, one per server	Not as is, scans files	Through OPDS
calibre plugins	Yes	Yes	Partly, in progress	No	No
Edit metadata	Yes	Yes	Yes, in batches too	Yes	In its own library
Convert formats	Yes, dozens	Yes, dozens	Yes, as books arrive	EPUB to Kobo only	No
Send to e-readers	Cable, wireless, email	Cable, wireless, email	Email, Kobo sync	Email, Kobo sync, KOReader	Not its job
Reading position sync	In the web reader	In the web reader	Kobo and KOReader	Web, iPhone, Kobo, KOReader	Its apps and KOReader
Licence	GPL v3	GPL v3	GPL v3	AGPL v3	AGPL v3
Price	Free	Free	Free	Free, paid extras on iPhone	Free, paid plans

In a browser, calibre-zen shows calibre’s own web app for now. A new web app is in progress for 0.5.0.

calibre-zen

A fork of calibre that draws its own interface and uses calibre as its engine. Plugins, news recipes, conversions, devices and your library all work as they do in calibre, with a modern, more accessible interface on top.

It installs beside calibre and leaves it as it was. Each calibre release is merged in about once a month, and it runs on calibre 9.15 today.

• You want everything calibre does, in a modern interface. The filters, book list, metadata editor and reader are all redesigned, in light, dim or dark.
• You want quality-of-life updates. Books open in about a tenth of a second, updates install from inside the app, and editing metadata takes a smaller window with grouped fields.
• You rely on plugins. Every calibre plugin runs as it does in calibre. The Plugins page lists the ones checked so far.
• You are moving from calibre. The welcome wizard brings over your library, settings and plugins in one click, and calibre stays untouched.
• You want your books in every browser at home. A Docker image shares the library, with a login and a folder that adds books. See Home server.
• You want sharing without a server. Close the window and the library stays shared from the menubar or tray. See Share with the window closed.

Where it is headed

The aim is calibre as a home server that has, out of the box, the features people go to Calibre-Web Automated or BookOrbit for. Version 0.4.0 made calibre easy to run with no window, which is the groundwork.

Version 0.5.0 is building a new web app on calibre’s own server, which you can install on a phone or a computer like an app. Browsing your library comes first. After that, the plan is to look at network drives and at running more than one copy of calibre at a time, two things calibre struggles with today.

Another tool may suit you better

• You want a phone app. There is none yet, so phones read in the browser.
• You want a modern web side today. The browser shows calibre’s own web app until the new one ships.
• You want signed Windows files. They are not signed yet, so SmartScreen warns once when you install.

calibre

The ebook manager calibre-zen is built on, and the library format Calibre-Web Automated uses. It manages, converts and sends books, on Windows, macOS and Linux. Get it from calibre-ebook.com.

• You want calibre exactly as its author ships it. The newest release is always here first.
• You convert a lot. It converts dozens of formats and has a built-in editor for EPUB and Kindle books.
• You load books onto e-readers. Send them over a cable, wirelessly, or by email.
• You read the news on your e-reader. It turns news sites and RSS feeds into books for your device.
• You want sharing with no window. The calibre-server program shares a library on its own, with no desktop needed.

Calibre-Web Automated

A web library for a home server, built on Calibre-Web with calibre’s tools inside. It opens an existing calibre library, or makes a new one. See it on GitHub.

• You want the whole library in a browser. Browse, read, edit and manage users from any device.
• You want new books handled for you. Drop files in a folder and they are converted, fixed and added. It can fill in metadata and email them to your e-reader too.
• You read on a Kobo or with KOReader. It syncs Kobo devices, and KOReader progress through its own plugin.
• You share with family. Each person gets their own account and permissions, with single sign-on if you use it.
• You like to tidy in bulk. Batch editing, duplicate finding and rule-based shelves are built in.

Good to know before you start.

• One library per server. More libraries need more copies running.
• calibre plugins are partly supported and still being worked on.
• Phones use the browser, or Calibre Web Companion, an unofficial Android app.

BookOrbit

A self-hosted home for ebooks, PDFs, comics and audiobooks. It is its own library, not built on calibre. See bookorbit.app and its GitHub page.

• You listen as well as read. Audiobooks sit beside ebooks and comics in one library.
• You read on an iPhone. A native iPhone and Apple Watch app works offline. Android is coming.
• You want your place kept everywhere. Progress and highlights sync between the web reader, Kobo and KOReader.
• You like reading stats. Goals, streaks and achievements are built in, with sync to Hardcover, Readwise and The StoryGraph.
• You are coming from Calibre-Web Automated. It imports metadata, progress and shelves from a CWA library.

Good to know before you start.

• It keeps its own library. It scans a folder of books into its own database rather than opening a calibre library as it is.
• It does not convert books, apart from making Kobo copies of EPUBs.
• It wants a local disk. Network shares like SMB and NFS are not supported.
• The server is free. The iPhone app is free too, with paid Premium extras.

Readest

A reading app for macOS, Windows, Linux, Android, iOS and the web. It is a reader first, with a library for the books you read. See readest.com.

• You want one reader on every device. Native apps for computers and phones, plus a web app.
• You want your notes everywhere. Highlights, notes and progress sync across your devices, and with KOReader.
• You read in another language. Look up words in a dictionary or Wikipedia, and translate a line or a whole book.
• You like to listen. It reads aloud, and plays read-along narration.
• You keep your books in calibre. A calibre plugin sends the books you pick to Readest, and your calibre files stay untouched.

Good to know before you start.

• It reads books rather than managing them. Converting and loading e-readers stay with a manager like calibre.
• Sync uses a Readest account. The free plan has 500 MB of cloud storage, and paid plans add more. You can host the sync yourself too.

Using them together

These tools pair well, since each one does a different part of the job.

• calibre-zen and Readest. calibre-zen’s server has an OPDS catalog at /opds, and Readest can browse one. Manage on the desktop and read in Readest.
• calibre-zen and Calibre-Web Automated. Both open an ordinary calibre library. Only one program should open a library at a time, so use them one after the other.
• A server and Readest. Calibre-Web Automated and BookOrbit both serve OPDS catalogs, which Readest can browse. Readest can also keep its reading progress in BookOrbit.

Last checked

October 2026, against calibre-zen 0.4.1, calibre 9.16, Calibre-Web Automated 4.0.8, BookOrbit 3.3.0 and Readest 0.12.12. Spot something out of date? Say so on r/CalibreZen or GitHub Issues.