Connect Komga, Kavita, or an OPDS server
Updated November 1, 2026.
ComicDuo is a client for comic servers you run yourself. Add a Komga or Kavita server, or any OPDS 1.2 catalog, and you can browse your library, stream pages, or download whole books on iPhone, iPad, and iPhone Duo. For books you stream, reading progress syncs back to Komga and Kavita. ComicDuo doesn't host a server and only connects to the addresses you enter.
Before you start
- Use https for anything outside your home network. Plain
http://works only for servers on your local network: private addresses such as192.168.x.xor10.x.x.x,.localnames, and names without a dot. - Self-signed certificates are accepted only on your local network, after you confirm the certificate's SHA-256 fingerprint. A server reachable from the internet needs a certificate from an authority such as Let's Encrypt.
- Local network permission. The first time ComicDuo reaches a server at home, iOS asks to let it find devices on your local network. Allow it. If you said no, turn it back on in the Settings app under Privacy & Security › Local Network › ComicDuo.
Add the server
- In the Library, tap Settings (the gear). Under Your files, tap Servers.
- Tap Add Server.
- Choose the Kind: Komga, Kavita, or OPDS. Komga is selected by default.
- Fill in Address and the sign-in fields as shown in the table below. Name is optional; if you leave it blank, ComicDuo uses the server's host name.
- Tap Test Connection. When it works you'll see “Connected to” followed by your catalog's name.
- Tap Save.
What to enter for each kind
| Kind | Address | Sign-in |
|---|---|---|
| Komga | The base address you open Komga with, such as https://komga.example.com or http://192.168.1.20:25600. ComicDuo adds /opds/v1.2/catalog itself. |
Username: your Komga email address. Password: your Komga password. |
| Kavita | The base address you open Kavita with, such as https://kavita.example.com or http://192.168.1.20:5000. ComicDuo adds /api/opds/ and your key itself. |
API key: copy it from your user settings in Kavita (in recent versions, 3rd Party Clients). |
| OPDS | The full catalog address, exactly as the server documents it. Works with Ubooquity, Calibre-Web, Stump, Codex, and other OPDS 1.2 servers. | Username and Password if the catalog asks for them; otherwise leave them empty. |
Don't paste a full OPDS link into the Komga or Kavita kind. Kavita's OPDS link already contains your API key, and ComicDuo would add the path a second time. If you only have that link, the OPDS kind will open it, but you lose progress sync.
Browse your library
Open a server from Settings › Servers, or tap Starter Shelf in the Library toolbar: your servers are listed at the top, and each one opens to its list of libraries. If you turn off Show Starter Shelf in Settings › Starter shelf, the same button reads Servers.
- A Search field appears when the server supports catalog search. Komga does.
- Long lists end with a Load More button.
Stream or download
Each book offers one or both of these, depending on what the server supports:
- Stream adds the book to your Library and opens it right away. Pages load from the server at your screen's resolution and are cached, so you need a connection while you read.
- Download copies the whole file into your Library for offline reading. Downloads continue in the background if you leave the app.
You can download a book you're streaming at any time with the Download button in the reader. Your place and collections carry over to the downloaded copy.
How progress sync works
- For books you stream from Komga or Kavita, ComicDuo sends your page back to the server when you close the reader or fold iPhone Duo shut. When you finish a book on Kavita, it's marked read.
- When you open a streamed book you haven't started in ComicDuo, it picks up at the page the server has. After that, the page in ComicDuo wins.
- Books you download, and books from plain OPDS servers, keep their progress in ComicDuo only. That progress still syncs between your own devices through iCloud.
On a second device
The list of servers is kept on each device, so add the server again on your iPad or second iPhone. Passwords and API keys are stored in the Keychain and sync through iCloud Keychain.
If something goes wrong
| Message | What to do |
|---|---|
| Enter a full server address, including https. | Start the address with https:// (or http:// for a server at home). |
| Plain http only works for servers on your local network. | Use the server's https address, or connect from your home network. |
| Sign-in failed. Check the username and password (or API key). | Komga signs in with your email address. For Kavita, copy the API key again. |
| No OPDS catalog at this address. | For Komga or Kavita, enter only the base address. For the OPDS kind, enter the full catalog address. |
| This server's certificate isn't signed by a trusted authority. | On your local network, ComicDuo offers Trust Certificate after Test Connection, or from Review Certificate when a catalog fails to open. Trust it only if the fingerprint matches your server's. Elsewhere, install a certificate from an authority such as Let's Encrypt. |
| The server's certificate is invalid or expired. | Renew the certificate, and check that the device's date and time are correct. |
What isn't supported
- Servers that offer only OPDS 2.0 (JSON) catalogs.
- Komga API keys, and Kavita username and password sign-in. Use a Komga password and a Kavita API key.
- Finding servers on the network automatically. Enter the address yourself.
- EPUB and CB7 files. ComicDuo opens CBZ, CBR, PDF, and folders of images.
Books from your server count toward the five-book trial, the same as any of your own files. Support and FAQ covers the trial and the purchase.