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:

You can also use the development image, and build a development container to work inside:

$ docker build -t cromwell-dev .
$ docker run -it cromwell-dev bash

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

NOTE: This command will run for a long time the first time.
NOTE: Compiling will not succeed on directories encrypted with ecryptfs (ubuntu encrypted home dirs for example), due to long file paths.

sbt assembly will build the runnable Cromwell JAR in server/target/scala-2.13/ with a name like cromwell-<VERSION>.jar. It will also build a runnable Womtool JAR in womtool/target/scala-2.13/ with a name like womtool-<VERSION>.jar.

To build a Docker image, run:

$ sbt server/docker

This will build and tag a Docker image with a name like broadinstitute/cromwell:<VERSION>-SNAP.