How to Set Up OPDS on iPhone & iPad

Quick answer: To set up OPDS on iPhone or iPad, install an OPDS-capable reader app, open its catalog section, add a new catalog by pasting the server's OPDS URL (for example http://192.168.1.10:8080/opds for a Calibre Content Server), and add a username and password only if the server asks for one. The app then lists everything on that server, ready to download and read offline.

OPDS is one of those features that sounds technical and turns out to take about two minutes. This guide explains what OPDS is, what you actually need to connect, and how to set up your first catalog on iPhone or iPad, whether that catalog is a free public library like Project Gutenberg or your own Calibre server at home.

What is OPDS?

OPDS (the Open Publication Distribution System) is a simple standard that lets a reading app browse and download books from a server. Think of it like an RSS feed, but for an ebook library instead of news articles. You point your app at one address, the catalog URL, and the app shows you every book the server offers, with covers, authors, and descriptions. You tap a book, it downloads, and you read.

Because it is an open standard, OPDS works across very different sources. The same app can connect to a public domain library, a home media server full of comics, and your personal Calibre collection, all through the same mechanism. Most apps and servers today speak OPDS 1.2. A newer JSON-based OPDS 2.0 exists and is starting to appear (Komga already supports it), but 1.2 is what you will use in practice.

What you need to connect

Connecting to any OPDS catalog requires only two things, and often just the first:

1. The catalog URL. This is the OPDS endpoint, usually ending in /opds or similar. For a public catalog it is published on the project's website. For your own server it is the server's address plus its OPDS path.
2. A username and password, only if required. Public catalogs are open. Private servers, like your own Calibre or Komga, can require a login. If so, you enter it once and the app remembers it.

That is the whole list. No accounts, no third-party sync service, no transferring files by hand.

Step 1: Install an OPDS reader

iOS does not browse OPDS catalogs on its own, so you need a reader app that supports it. justRead is an EPUB and PDF reader for iPhone and iPad with OPDS built in, including a bundled Project Gutenberg catalog, server-side search, and support for custom servers. Whichever app you choose, look for an OPDS or Catalogs section in its library or settings.

Step 2: Add your first catalog (Project Gutenberg)

The easiest way to see OPDS work is a free public catalog. Project Gutenberg offers more than 70,000 public domain books through an OPDS feed at:

https://www.gutenberg.org/ebooks/search.opds/

In justRead, Project Gutenberg is built in, so you can open it directly without typing anything. In other apps, open the OPDS section, choose Add Catalog, paste the URL above, and save. The app loads the catalog, and you can browse or run a search for an author or title, then download anything you like. Everything on Gutenberg is free and legal to download.

Step 3: Connect a Calibre Content Server

The most popular private catalog is your own Calibre library. Calibre, the free desktop ebook manager, can publish your whole collection over OPDS in a couple of clicks:

1. On your computer, open Calibre and click Connect/share in the toolbar.
2. Choose Start Content Server.
3. Note your computer's local IP address (something like 192.168.1.10). The OPDS endpoint is then http://192.168.1.10:8080/opds, where 8080 is Calibre's default port.

On your iPhone or iPad, add that URL as a new OPDS catalog. justRead can also discover a Calibre Content Server on the same Wi-Fi automatically, and it supports HTTP Digest authentication if you have turned on Calibre's "Require username and password" option. For a fuller workflow that syncs reading progress and ratings back to your computer, see the dedicated Calibre library sync guide. This OPDS route is the quickest way to simply read your books.

A few things to know about the Content Server: Calibre has to stay open and running for the catalog to work, both devices must be on the same network unless you set up remote access, and if your computer's IP address changes, the catalog URL changes with it. Reserving a static IP in your router avoids that.

Step 4: Connect a self-hosted server (Komga, Kavita, calibre-web)

If you run a home server, the same steps apply with each project's OPDS endpoint:

justRead supports custom OPDS servers including Calibre OPDS, calibre-web, Kavita, Komga, and COPS, with per-server filtering and pagination so even large catalogs stay manageable. Add the server as a new catalog, enter credentials if needed, and your shelves appear on your iPhone.

One quirk worth flagging: Kavita does not use a separate username and password for OPDS. Instead it builds an authentication key into the URL itself (the <your-key> part above). Copy the full pre-built URL from Kavita's settings, paste it as the catalog URL, and leave the username and password fields blank.

Common problems and fixes

• The app cannot reach the server. Confirm both devices are on the same Wi-Fi, the server software is running, and you used http:// with the correct port. A computer firewall blocking the port is the usual culprit.
• It asks for a login you do not have. The server has authentication enabled. Use the same credentials you set on the server, or turn the requirement off for local-network use.
• A remote server will not connect over HTTPS. iOS rejects self-signed certificates unless you install and explicitly trust them in Settings. For remote access, a proper certificate (for example via a domain and Let's Encrypt) is the reliable path.
• The catalog worked yesterday and not today. Your server's local IP probably changed. Reserve a static IP, or use the computer's .local hostname instead of the numeric address.

Where OPDS fits in your reading setup

OPDS turns your iPhone or iPad into a front end for any library you can point it at, public or private, without copying files around by hand. Once it is set up, downloading a new book is two taps. To go deeper on connecting catalogs and servers, see the OPDS reader overview, and if your books live in Calibre, the Calibre sync workflow adds two-way progress and rating sync on top. New to ebooks on iOS in general? Start with how to read EPUB on iPhone and iPad.

Download justRead on the App Store to set up your first OPDS catalog today.