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Find out how to help translate or build the app and parsers.

App contribution guidelines

  • If you want to fix bug or implement a new feature, that already mention in the issues, please, assign this issue to you and/or comment about it.
  • Whether you have to implement new feature, please, open an issue or discussion regarding it to ensure it will be accepted.
  • Translations have to be managed using the Weblate platform.
  • In case you want to add a new manga source, refer to the parsers repository.

Refactoring or some dev-faces improvements are also might be accepted, however please stick to the following principles:

  • Performance matters. In the case of choosing between source code beauty and performance, performance should be a priority.
  • Please, do not modify readme and other information files (except for typos).
  • Avoid adding new dependencies unless required. APK size is important.

Parsers contribution guidelines

The following is guide for creating a Kotatsu parsers. Thanks for taking the time to contribute!


Before you start, please note that the ability to use following technologies is required.


Kotatsu parsers is not a part of Android application, but you can easily develop and test it directly inside an Android application project and relocate it to the library project when done.

Before you start

First, take a look at kotatsu-parsers project structure. Each parser is a single class that extends MangaParser class and have a MangaSourceParser annotation. Also pay attention on extensions in util package. For example, extensions from Jsoup file should be used instead of existing JSoup functions because they have better nullability support and improved error messages.

Writing your parser

So, you want to create a parser, that will provide access to manga from a website. First, you should explore a website for API availability. If it does not contain any documentation about API, explore network requests: some websites use ajax.

If website is based on some engine it is rationally to use common base class for this one (for example, Madara wordress theme and the MadaraParser class)

Parser class skeleton

Parser class must have exactly one primary constructor parameter of type MangaLoaderContext and have an MangaSourceParser annotation that provides internal name, title and language of a manga source.

All functions in MangaParser class are documented. Pay attention to some peculiarities:

  • Never hardcode domain. Specify default domain in configKeyDomain field and obtain an actual one using getDomain().
  • All ids must be unique and domain-independent. Use generateUid functions with relative url or some internal id which is unique across the manga source.
  • sortOrders set should not be empty. If your source is not support sorting, specify one most relevance value.
  • If you cannot obtain direct links to pages images inside getPages method, it is ok to use an intermediate url as Page.url and fetch a direct link at getPageUrl function.
  • You can use asserts to check some optional fields. For example. field is not required, but if your source provide such information, add assert(it != null). This will not have any effect on production but help to find issues during unit testing.
  • If your source website (or it's api) uses pages for pagination instead of offset you should extend PagedMangaParser instead of MangaParser.
  • Your parser may also implement the Interceptor interface for additional manipulation of all network requests and/or responses, including image loading.

Development process

During the development it is recommended (but not necessary) to write it directly in the Kotatsu android application project. You can use core.parser.DummyParser class as a sandbox. Dummy manga source is available in debug Kotatsu build.

Once parser is ready you can relocate your code into kotatsu-parsers library project in a site package and create a Pull Request.


It is recommended to run unit tests before submitting a PR.

  • Temporary modify the MangaSources annotation class: specify your parser(s) name(s) and change mode to EnumSource.Mode.INCLUDE
  • Run the MangaParserTest
gradlew :test --tests "org.koitharu.kotatsu.parsers.MangaParserTest"
gradlew :test --tests "org.koitharu.kotatsu.parsers.MangaParserTest"
  • Optionally, you can run the generateTestsReport gradle task to get a pretty readable html report from test results.


If you need a help or have some questions, ask a community in our Telegram chat or Discord server.