Wercker, a startup with tools for automating the process of testing and deploying code, is announcing today a $4.5 million funding round. The startup is also announcing that it’s releasing its command line interface (CLI) tool under an open-source license on GitHub.

With the new funding, Wercker can build out a full commercial product with features that big companies would like, founder and CEO Micha Hernandez van Leuffen told VentureBeat in an interview.

Competitors include Codeship, CircleCI, Drone.io, Semaphore, and Shippable.

One key point of differentiation is Wercker’s integration with Docker containers, which package up application code and can be easily moved from server to server.

“All our jobs work inside Docker containers,” Hernandez van Leuffen said. “If you’d like, each build artifact can be a Docker container.” And you can take a container from the Docker Hub or your own private registry and then build the code before shipping it. Plus, now that the CLI is open-source, people can build on it.

Inkef Capital led the new funding round, with participation from Notion Capital. To date, Wercker has raised $7.5 million.

Wercker started in 2011 and is based in Amsterdam, with an office in San Francisco and 17 employees. Last year the startup introduced the Organizations feature. Tens of thousands of people currently use Wercker, Hernandez van Leuffen said.

Wercker integrates with GitHub and Atlassian’s Bitbucket. It doesn’t currently support GitLab.