Jenkins vs Github Actions comparison of Continuous Integration servers
What are the differences between Jenkins and Github Actions?

Plugins

Best GitHub integration possible

Self-hosted / On Premise

SaaS / On Premise

Yes

Free, open source software

Yes

The on premise plan (not yet available) will be free, 2000 build minutes included in the free cloud plan. Completely free plan for open source projects.

Yes

Jenkins is free software, the only costs are those assigned to running your infrastructure.

Yes (partial)

While it's clear what the cost is (priced per build-minute), figuring out costs can be a hassle, especially as the price can vary quite a bit depending on commits to the project. One advantage for GitHub Actions is that the tiers define a maximum amount of minutes, so it's easier to predict the final cost. You can also purchase aditional runners with pricing dependent on the platform (MacOS, Linux, Windows)

No (partial)

No official support available, or SLAs. However, Jenkins' popularity ensures you'll find support in various places (official Jenkins forum, IRC, StackOverflow etc.)

Yes

Community support available for any tier, unclear at what point and if dedicated support is available. Safe to assume that eneterprise clients can access technical support.

Yes (partial)

Jenkins allows builds to be run in parallel, but all builds share the same environment and there can be issues arising from shared resources such as the filesystem.

Yes

Matrix builds allow concurrent jobs, even multi-platform.

Yes (partial)

Jenkins has a concept of master server and agents, for distributing builds, but setting that up requires quite a bit of manual work from a sysadmin, compared to other options.

N/A

No specific mention, but given the fact that tasks can be run on multiple platforms, it's likely that distributed builds are also available.

No (partial)

By default, Jenkins runs all builds in the same environment as the build server itself, which can lead to numerous issues and is generally not a good practice. Some plugins address this issue, but they need to be manually installed.

Yes

Linux, macOS, Windows, and containers, or run directly in a VM.

Yes

Available via the Blue Ocean project (part of Jenkins): https://jenkins.io/doc/book/blueocean/dashboard/#dashboard

Yes

Minimal status overview definitely available, with live logs and GitHub integration. Unclear how far it goes.

No

In practice, for Jenkins it usually means that there's someone solely in charge of the Jenkins instance (configuration, management). Collaboration features built into other similar products are lacking, as are governance features (no easy way to tell from Jenkins alone _who_ is responsabile for a broken build, for example), even if your Version Control Server of choice can give that information (via `git blame` for example).

N/A

Unclear from the available documentation

Yes

Jenkins is Open Source Software, and self-hosting is the only way to use it.

Yes

Coming soon, not available yet.

No

Only available for self-hosting.

Yes

Yes

Offers extensive support for custom pipelines, either through the Jenkins Pipeline DSL, written in a Jenkinsfile, either through the Web UI. Also, their Blue Ocean project is a great tool for building pipelines: https://jenkins.io/projects/blueocean/

Yes

Called GitHub Action Workflows, they are defined in separate Docker containers, using the YAML syntax (they used to support HCL, but they're migrating away from that)

Yes

Has ready-made integrations for standard reports such as JUnit test results.

N/A

Unclear from the available documentation

> 1000 community plugins

Thanks to it's popularity, there's a large selection of available plugins for Jenkins. They can all be easily browsed over at https://plugins.jenkins.io/. The downside is that almost anything you want to do in Jenkins requires installing a plugin, even core functionality such as parsing output or checking out source code.

Yes

Thanks to the large following, GitHub Actions already enjoys a wide varierty of available pre-made workflows, which you can browse right on the homepage: https://github.com/features/actions

Yes (Partial)

RSpec and Cucumber test suites can be integrated into Jenkins thanks to the large pool of available plugins and Ruby gems. Jenkins only understands the JUnit format natively.

Yes

Unclear how, but they mention Ruby support specifically on the homepage

Yes (Partial)

Jest, AVA and other test suites can be integrated into Jenkins thanks to the large pool of available plugins and NPM packages. Jenkins only understands the JUnit format natively.

Yes

Unclear how, but they mention Javascript (Node.js) support specifically on the homepage

Yes

Allows integrations with other tools (ie: Slack, GitHub) or communication protocols (ie: email) via it's rich plugin suite

Yes

Integrations made possible via the shared third party workflows available (AWS, Azure, Zeit, Kubernetes and many more)

Yes

For use-cases that the +1k plugins don't cover, the Jenkins Remote API is yet another way to integrate Jenkins into your favorite tools or internal products.

N/A

Unclear at the moment, but assume GitHub Actions will be integrated with the GitHub GraphQL API (one of the more mature GraphQL API implementations available)

No

Jenkins instances are really managed by a sole user with administrative privileges. This can lead to various issues when it comes to audit trails / accountability.

N/A