Most users should not need to build Cromwell and can use pre-built Cromwell releases.

If for some reason you require a non-release version of Cromwell or are developing new Cromwell features or fixes, the following are required to build Cromwell from source:

First start by cloning the Cromwell repository from GitHub:

$ git clone

Next change into the cromwell directory:

$ cd cromwell

If you require a specific version of Cromwell as a starting point, do the appropriate git checkout now.

Finally build the Cromwell jar:

$ sbt assembly

sbt assembly will build the runnable Cromwell JAR in server/target/scala-2.12/ with a name like cromwell-<VERSION>.jar.