A minimalistic, simple-to-use API linter

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Zally: A minimalistic, simple-to-use API linter

Zally brings order to your sea of APIs. Use it to:

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.

More about Zally:

Technical Dependencies

Find additional details here. With Spring 5, we consider using Kotlin also directly on the API side.

Installation and Usage

To give Zally a quick try, first run the server locally and then use the CLI tool.

The Server Readme, CLI Readme and Web UI Readme include more detailed installation steps for each component.

Quick start guide

git clone zally
cd zally

# Disable authentication and start a local version of Zally server
cd server
./gradlew clean build
./gradlew bootRun > /dev/null &
cd ..

# Build CLI tool
cd cli/zally
go build
./zally lint /path/to/swagger/definition.yaml


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.


For Zally version 1.2, we’re focusing on:

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


Feel free to contact one the maintainers.


MIT license with an exception. See license file.