Zally: A minimalistic, simple-to-use OpenAPI 2 and 3 linter

Zally is a quality assurance tool. It’s a linter for OpenAPI specifications, which:

• Increases the quality of APIs
• Checks compliance
• Delivers early feedback for API designers
• Ensures the same look-and-feel of APIs
• Supports API-First approach
• Provides best practices and advices

Its standard configuration will check your APIs against the rules defined in Zalando’s RESTful Guidelines, but anyone can use it out-of-the-box.

Zally’s easy-to-use CLI uses the server in the background so that you can check your API on the spot. It also features an intuitive Web UI that shows implemented rules and lints external files and (with its online editor) API definitions.

Features

• Support for OpenAPI 3 and (Swagger) OpenAPI 2 specifications
• RESTful API, CLI and Web interface
• Rich Check configuration
• Ignore functionality (x-zally-ignore extension)
• Java/Kotlin API for new Checks + helper functions

Quick start guide

Trying out Zally is easy. You can build and run the whole Zally stack (web-ui, server and database) by executing:

./build-and-run.sh

Web UI is accessible on http://localhost:8080; Zally server on http://localhost:8000

Documentation and Manuals

Please consult the following documents for more information:

• Zally Concepts
• How to operate Zally tools
• How to use Zally
• How to develop new Rules
• Building Under Windows Subsystem for Linux

Contributing

Zally welcomes contributions from the open source community. To get started, take a look at our contributing guidelines. Then check our Project Board and Issues Tracker for ideas.

Roadmap

For Zally version 1.5, we’re focusing on:

• Improve extensibility of Zally
  • Plugin mechanism for Rules (Sets)
  • Utilities and helper functions for Check development
• Improve quality by introducing a better testing approach for integration tests
• Make the usage of Zally easier by providing high-quality documentation for
  • End users
  • Check developers
  • Operators and administrators

If you have ideas for these items, please let us know.

Contact

Feel free to join our Gitter room or contact one of the maintainers directly.

Alternatives

Zally is not the only linter for OpenAPI v2 and v3. There is an article comparing different OpenAPI linters.

So why should you choose Zally?

• It supports Zalando’s RESTful Guidelines
• It can be used in multiple ways: RESTful API, CLI and Web interface
• Highly customizable (with Kotlin)

License

MIT license with an exception. See license file.

Publish

Prerequisites

• Signing plugin configured
• OSSRH_JIRA_USERNAME and OSSRH_JIRA_PASSWORD environment variables to access Maven Central Repo are configured

Steps

1. Create a separate branch with a name release-<release-version>.
2. Update current version in server/gradle.properties from -SNAPSHOT to a final version.
3. Release Zally server and API using the command

   cd server
   ./gradlew clean build publishAllPublicationsToMavenRepository
   

4. Commit server/gradle.properties with the release version
5. Create a tag shell script git tag v<release-version> -m "Version <release-version>"

6. Bump version in server/gradle.properties to the next -SNAPSHOT

7. Push release branch and tag shell script git push origin git push origin <tag-name>
8. Create a Pull Request with the version update
9. Create and publish a release with a new version in GitHub