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brew tap endava/tap
brew install cats


CATS is bundled both as an uberjar JAR or a native binary. The native binaries do not need Java installed.

After downloading your OS native binary, you can add it to PATH and execute it as any other command line tool:

sudo cp cats /usr/local/bin/cats

cats -h

You can also run CATS using the uberjar. This requires Java 17+ to be installed.

You can run it as java -jar cats.jar.


There is no native binary for Windows, but you can use the uberjar version.

Head to the releases page to download the latest version:


You can also get autocomplete in bash or zsh by downloading the cats_autocomplete script and do:

source cats_autocomplete

To get persistent autocomplete, add the above line in .zshrc or .bashrc, but make sure you put the fully qualified path.


You can also check the cats_autocomplete source for alternative setup.

Build from sources

You can build CATS from sources on you local box. You need Java 17+. Maven is already bundled.

Before running the first build

Before running the first build, please make sure you do a ./mvnw clean. CATS uses a fork ok OKHttp which will install locally under the 4.10.0-CATS version, so don't worry about overriding the official versions.

You can use the following Maven command to build the project as an uberjar:

./mvnw package -Dquarkus.package.type=uber-jar

You will end up with a cats-runner.jar in the target folder. You can run it wih java -jar cats-runner.jar ....

You can also build native images using a GraalVM Java version.

./mvnw package -Pnative


You will need to configure Maven with a Github PAT with read-packages scope to get some dependencies for the build.

Notes on Unit Tests

You may see some error log messages while running the Unit Tests. Those are expected behaviour for testing the negative scenarios of the Fuzzers.