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Contributing Guidelines

There are two main ways to contribute to the project — submitting issues and submitting fixes/changes/improvements via pull requests.

Submitting issues

Both bug reports and feature requests are welcome. Submit issues here.

  • Search for existing issues to avoid reporting duplicates.
  • When submitting a bug report:
    • Use a 'bug report' template when creating a new issue.
    • Test it against the most recently released version. It might have been already fixed.
    • By default, we assume that your problem reproduces in Kotlin/JVM. Please, mention if the problem is specific to Kotlin/JS or Kotlin/Native.
    • Include the code that reproduces the problem. Provide the complete reproducer code, yet minimize it as much as possible.
    • However, don't put off reporting any weird or rarely appearing issues just because you cannot consistently reproduce them.
    • If the bug is in behavior, then explain what behavior you've expected and what you've got.
  • When submitting a feature request:
    • Use a 'feature request' template when creating a new issue.
    • Explain why you need the feature — what's your use-case, what's your domain.
    • Explaining the problem you face is more important than suggesting a solution. Report your problem even if you don't have any proposed solution.
    • If there is an alternative way to do what you need, then show the code of the alternative.

Submitting PRs

We love PRs. Submit PRs here. However, please keep in mind that maintainers will have to support the resulting code of the project, so do familiarize yourself with the following guidelines.

  • All development (both new features and bug fixes) is performed in the dev branch.
    • The master branch always contains sources of the most recently released version.
    • Base PRs against the dev branch.
    • The dev branch is pushed to the master branch during release.
    • Documentation in markdown files can be updated directly in the master branch, unless the documentation is in the source code, and the patch changes line numbers.
  • If you fix documentation:
    • After fixing/changing code examples in the docs folder or updating any references in the markdown files run the Knit tool and commit the resulting changes as well. It will not pass the tests otherwise.
    • If you plan extensive rewrites/additions to the docs, then please contact the maintainers to coordinate the work in advance.
  • If you make any code changes:
  • If you fix a bug:
    • Write the test the reproduces the bug.
    • Fixes without tests are accepted only in exceptional circumstances if it can be shown that writing the corresponding test is too hard or otherwise impractical.
    • Follow the style of writing tests that is used in this project: name test functions as testXxx. Don't use backticks in test names.
  • If you introduce any new public APIs:
    • All new APIs must come with documentation and tests.
    • All new APIs are initially released with @ExperimentalSerializationApi annotation and are graduated later.
    • Update the public API dumps and commit the resulting changes as well. It will not pass the tests otherwise.
    • If you plan large API additions, then please start by submitting an issue with the proposed API design
      to gather community feedback.
    • Contact the maintainers to coordinate any big piece of work in advance.
  • If you propose/implement a new serialization format:
    • Follow the general advice on new public APIs above.
    • Note, that you can keep new format implementation in your own repository to be able to perform proper maintenance and to have a separate release cycle.
    • You can submit a PR to the list of community-supported formats with a description of your library.
  • Comment on the existing issue if you want to work on it. Ensure that the issue not only describes a problem, but also describes a solution that had received a positive feedback. Propose a solution if there isn't any.


You can find all the instructions here

Running the Knit tool

  • Use Knit for updates to documentation:
    • Run ./gradlew knit to update example files, links, tables of content.
    • Commit updated documents and examples together with other changes.

Updating the public API dump

  • Use Binary Compatibility Validator for updates to public API:
    • Run ./gradlew apiDump to update API index files.
    • Commit updated API indexes together with other changes.


  • Full release procedure checklist is here.

Contacting maintainers

  • If something cannot be done, not convenient, or does not work — submit an issue.
  • "How to do something" questions — StackOverflow.
  • Discussions and general inquiries — use #serialization channel in KotlinLang Slack.