Bamboo vs Circle CI comparison of Continuous Integration servers
What are the differences between Bamboo and Circle CI?

Atlassian suite integration

Premium Support

On Premise

SaaS, Self-hosted / On Premise

Yes

The full Atlassian suite is free for open source projects (https://www.atlassian.com/software/views/open-source-license-request). For all others, they offer a minimal free trial.

Yes

Provides a free plan for it's SaaS solution, for up to 1000 build minutes per month, 1 container and 1 concurrent job. On top of this, it has a special Free Tier for open source projects, which extend the number of containers and concurrent jobs available.

Yes

They price their product based on number of build agents (more concurrency, more expensive). Given the notoriety and depth of the Atlassian suite, the pricing can be steep for small companies.

Yes

Provides a calculator, based on the number of concurrent jobs and containers, which can be used to determine pricing before purchase. They also give a guideline based on the number of developers you employ (2-3 containers per full-time developer)

Yes

Dedicated tehnical support.

Yes

While it's community is not quite as vibrant as it is for Jenkins, CircleCI even offers support premium support for companies who cannot afford any downtime in their CI/CD pipelines (https://circleci.com/support/premium-support/). For the regular plans, all plans except the free tier offer official email support. The free tier only includes community support (Discuss, StackOverflow, etc.)

Yes

Up to 100 parallel agents

Yes

CircleCI can run builds in parallel, each build in a completely isolated environment by using containers.

Yes

Agents can run on multiple machines.

Yes

The SaaS version distributes builds by default, while the self-hosted version has all the tools built-in for managing the cluster of builder machines.

Yes

By default, they offer Docker support for the CI/CD job runners.

Yes

CircleCI runs every build in a container, or VM, ensuring an isolated, local scope for each build. The environment is also reset with each build, which can highlight hard-to-track issues related to assumptions about the environment that the project is deployed to.

Yes

Excellent dashboards, even more so thanks to integrations with the other tools in the Atlassian arsenal

Yes

Available by default in Circle CI: https://circleci.com/docs/2.0/status/#section=jobs. Aditionally, the Insights Dashboard provides a very useful overview on build times, error rates and status for your projects: https://circleci.com/docs/2.0/insights/#section=jobs

Yes

Great management support, built for large scale companies, even allows setting per-environment permissions (ie: QA team can only deploy to their own, isolated environment)

No (partial)

Using the Cloud plan for Circle CI requires no dedicated person for maintanence / management of the service. The CircleCI Server option (self-hosted) is also hassle free, as the process of installing and managing CircleCI and it's dependencies is automated. Developers are also given SSH acces to the builds (not the whole environment), while sys-admins can work on the host machine without worry about affecting the builds (which are containerized).

Yes

Yes

No

Yes

Yes

Advanced pipeline support - with features built for feature branch support, various triggers, schedules, external notifications and more.

Yes

Pipelines in CircleCI are defined declaratively using an Yaml config file. CircleCI has special provisions for storing secrets in these files.

Yes

Yes

Reports are available

Yes

Large selection (~200) of apps that integrate with Bamboo, available on the official marketplace for Bamboo: https://marketplace.atlassian.com/addons/app/bamboo

Yes, partially

While CircleCI doesn't natively support plugins, it's core features address all of the core functionality that a CI/CD service needs. For integrating with other platforms or tools, there are integrations such as https://slack.com/apps/A0F7VRE7N-circleci. Certain jobs are available as CircleCI Orbs: https://circleci.com/orbs/

Yes (partial)

It looks like the documentation and features for Ruby are lagging behind. All I could find is this repo: https://github.com/drscream/bamboozled-ruby-plugin, following this support ticket: https://jira.atlassian.com/browse/BAM-10948 from this documentation stub page: https://confluence.atlassian.com/bamboo0601/getting-started-with-ruby-and-bamboo-935580774.html

Yes

For collecting test metadata and coverage, there is built-in support for Ruby (specifically, Cucumber and RSpec). Setting this up takes very little time and is well-documented on CircleCI's docs.

No

No specific support, beyond some documentation on integrating Selenium (not marked as partial support since that documentation is only promoted in the Atlassian docs, but is hosted by BrowserStack)

Yes

For collecting test metadata and coverage, there is built-in support for Javascript. For code coverage, CircleCI understands Istanbul output (Jest also uses Istanbul for the code coverage reports), while for test metadata, the JUnit output format is natively supported.

Yes

Deep integration with the Atlassian product stack (Jira, etc.).

Yes

Available as CircleCI Orbs: https://circleci.com/orbs/

Yes

Yes

REST API documentation available at https://circleci.com/docs/api/#api-overview. Creating Orbs is also documented at https://circleci.com/docs/2.0/orb-author/#introduction

Yes

N/A

Not really something that should be purchased separatelly from the Atlassian stack.