CircleCI vs. GitHub Actions vs. GitLab: Key Differences

When organizations plan to introduce a continuous integration (CI) pipeline (or modernize the one they have), they’ll come across quite a few options. This article covers three of the most widely used solutions: CircleCI, GitHub Actions, and GitLab CI/CD. These solutions provide the capability to extend beyond basic building and deployments, adding support for test automation and other components that will improve the integrity of the software you deliver.

CircleCI aims to provide a best-in-class continuous integration and continuous delivery (CI/CD) platform for use by development teams. It has already proven itself, and you can find case studies about how it has performed for customers ranging in size from startups to multinational companies (and household names like PayPal).

GitHub Actions is the CI/CD functionality within the GitHub platform. GitHub’s platform is the most widely used Git platform on the planet, and it has extensive functionality beyond just Actions – including defect and project tracking, image repositories, and analytics. It was purchased by Microsoft in 2018.

GitLab CI/CD extends the GitLab platform to allow developers to run continuous integration and delivery pipelines against their code repositories. Much like GitHub, GitLab offers a full suite of functionality that developers can leverage throughout their development cycles.

GitLab uses an open core model, so its base functionality is open source. As a result, it’s probably the most widely used Git repository within corporate data centers, even though the CI/CD integration is not included in the open core.

One of the biggest benefits of having CI/CD pipelines is the ability to enhance them with additional checks and validation points to ensure that reliable software is being delivered to the customer in a fast and consistent way. Leveraging continuous testing is a key part of this initiative.

In CircleCI, you can add continuous testing into a pipeline as a series of steps within a job. Alternatively, as with Sauce Labs, you can use an orb from the CircleCI library that will handle most of the heavy lifting, and the test suite can be run in a single step. The sample YAML below imports the orb and then runs it within the job as a single step by passing it in the directory in which the application is stored.

Enabling continuous testing in GitHub Actions works much the same way as in CircleCI, except that a prebuilt container is often used for testing purposes instead of an orb. In this case, you define the secrets used to access the container in question, then run the container with the appropriate flags and the location of the working directory where the application you want to test resides.

The CI/CD options from GitLab, in my opinion, do not seem to have the same level of support in the ecosystem for prebuilt items to help with continuous testing. Ultimately, this really isn’t a big deal, but it means that you’ll have to add an extra item or two to the YAML so that the latest tools are downloaded instead of being able to pull an image with a single line. Again, as with the other CI tools, a single command is run in the workflow with some parameters included in a configuration file (primarily the location of the application to test).

Selecting the best CI/CD solution can feel like a daunting task because there are lots of things to consider. All three options reviewed in this article will meet the needs of most developers who desire to improve (or create) the CI/CD pipelines that handle their builds, tests, and even deployments. These platforms all work with technology partners to add additional capabilities that make their solutions more robust than they could have achieved on their own. For example, see the documentation about integrations with Sauce Labs.

Choosing the CI platform that’s best for your organization really comes down to your goals. CircleCI is arguably the best option overall, as it is purpose-built with CI/CD pipelines as its core focus. On the other hand, many organizations find that GitLab and GitHub meet all their needs. In addition, these solutions often work better for organizations that aim to simplify their support structures by utilizing fewer vendors.