CircleCI

CircleCI is a usage-based CI/CD platform for software teams that build, test and deploy on hosted or self-hosted runners.

CircleCI turns a config file in the repository, .circleci/config.yml, into pipelines that run each time code changes or on a schedule. Circle Internet Services, Inc. makes it in San Francisco, where the company was founded in 2011. Builds, tests and releases start on hosted machines or on the team's own without someone running them by hand. Pipelines start on push and pull request events, and Schedule Triggers run them at set times from the web app or the API. Matrix jobs and parallelism spread work across versions, platforms and test shards, while dependency caching and Docker Layer Caching let jobs skip repeated downloads. Orbs package reusable, parameterizable configuration that projects import instead of rewriting. Contexts hold secrets that are masked in job output, OpenID Connect tokens let jobs reach cloud services without long-lived credentials stored in CircleCI, and approval jobs in workflows pause a deploy for manual sign-off. Test reports show flaky tests and the slowest tests, and job artifacts save and link screenshots, coverage reports and tarballs. CircleCI suits software teams that want usage-based CI/CD, from small groups starting on the Free plan to larger organizations on Scale. Platform and DevOps engineers can run jobs on their own machines through self-hosted runners, while the hosted resources cover Docker, Linux, Windows, Arm and macOS builds. Organizations that want the whole platform on their own infrastructure can install CircleCI Server on AWS or GCP. A startup program gives qualifying startups free compute credits. CircleCI is bought as credits under the Free, Performance, Scale and Server plans. Teams use CircleCI to build and test on each push, run pull request checks, split test suites, run nightly jobs and deploy to cloud providers such as AWS and Google Cloud. It works with GitHub, Bitbucket and GitLab for source code, and with PyPI and Artifactory for packages. Runners registered under Self-Hosted Runners in the web app sit beside CircleCI's hosted resources, so one organization can run jobs in both places.