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Automate your development process quickly, safely, and at scale

What is CircleCI?

Continuous integration and delivery platform helps software teams rapidly release code with confidence by automating the build, test, and deploy process. Offers a modern software development platform that lets teams ramp.
CircleCI is a tool in the Continuous Integration category of a tech stack.

Who uses CircleCI?

1702 companies reportedly use CircleCI in their tech stacks, including Instacart, LaunchDarkly, and Stripe.

7014 developers on StackShare have stated that they use CircleCI.

CircleCI Integrations

JavaScript, GitHub, Python, Node.js, and Slack are some of the popular tools that integrate with CircleCI. Here's a list of all 124 tools that integrate with CircleCI.
Pros of CircleCI
Github integration
Easy setup
Fast builds
Competitively priced
Slack integration
Docker support
Awesome UI
Great customer support
Ios support
Hipchat integration
SSH debug access
Free for Open Source
Bitbucket integration
Mobile support
Nodejs support
AWS CodeDeploy integration
Great support
Free for Github private repo
YAML configuration
OSX support
Continuous Deployment
Simple, clean UI
Helpful documentation
Extremely configurable
Android support
Fair pricing
All inclusive testing
Japanese in rspec comment appears OK
Build PR Branch Only
So circular
Easy setup, easy to understand, fast and reliable
Parallel builds for slow test suites
Easy setup. 2.0 is fast!
Easy to deploy to private servers
Really easy to use
Decisions about CircleCI

Here are some stack decisions, common use cases and reviews by companies and developers who chose CircleCI in their tech stack.

Hi, I am doing automation for mobile app (iOS & Android). Currently, I am using Apache Maven build tool. Can someone tell me which out of these 3 tools is the best? (fastlane, Gradle, Maven). Apart from that, we are using CircleCI.

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Paxion Tang
Sr Staff at trendmicro · | 2 upvotes · 21.5K views
Shared insights
Microsoft AzureMicrosoft AzureCircleCICircleCI

My project need to use CircleCI and deploy to Microsoft Azure. Where can i start ? Thanks

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Somnath Mahale
Engineering Leader at Altimetrik Corp. · | 8 upvotes · 153.6K views

I am in the process of evaluating CircleCI,, and Github Actions to cover my #CI/ CD needs. I would appreciate your advice on comparative study w.r.t. attributes like language-Inclusive support, code-base integration, performance, cost, maintenance, support, ease of use, ability to deal with big projects, etc. based on actual industry experience.

Thanks in advance!

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Simon Reymann
Senior Fullstack Developer at QUANTUSflow Software GmbH · | 29 upvotes · 5.3M views

Our whole DevOps stack consists of the following tools:

  • GitHub (incl. GitHub Pages/Markdown for Documentation, GettingStarted and HowTo's) for collaborative review and code management tool
  • Respectively Git as revision control system
  • SourceTree as Git GUI
  • Visual Studio Code as IDE
  • CircleCI for continuous integration (automatize development process)
  • Prettier / TSLint / ESLint as code linter
  • SonarQube as quality gate
  • Docker as container management (incl. Docker Compose for multi-container application management)
  • VirtualBox for operating system simulation tests
  • Kubernetes as cluster management for docker containers
  • Heroku for deploying in test environments
  • nginx as web server (preferably used as facade server in production environment)
  • SSLMate (using OpenSSL) for certificate management
  • Amazon EC2 (incl. Amazon S3) for deploying in stage (production-like) and production environments
  • PostgreSQL as preferred database system
  • Redis as preferred in-memory database/store (great for caching)

The main reason we have chosen Kubernetes over Docker Swarm is related to the following artifacts:

  • Key features: Easy and flexible installation, Clear dashboard, Great scaling operations, Monitoring is an integral part, Great load balancing concepts, Monitors the condition and ensures compensation in the event of failure.
  • Applications: An application can be deployed using a combination of pods, deployments, and services (or micro-services).
  • Functionality: Kubernetes as a complex installation and setup process, but it not as limited as Docker Swarm.
  • Monitoring: It supports multiple versions of logging and monitoring when the services are deployed within the cluster (Elasticsearch/Kibana (ELK), Heapster/Grafana, Sysdig cloud integration).
  • Scalability: All-in-one framework for distributed systems.
  • Other Benefits: Kubernetes is backed by the Cloud Native Computing Foundation (CNCF), huge community among container orchestration tools, it is an open source and modular tool that works with any OS.
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Emanuel Evans
Senior Architect at Rainforest QA · | 20 upvotes · 1.1M views

We recently moved our main applications from Heroku to Kubernetes . The 3 main driving factors behind the switch were scalability (database size limits), security (the inability to set up PostgreSQL instances in private networks), and costs (GCP is cheaper for raw computing resources).

We prefer using managed services, so we are using Google Kubernetes Engine with Google Cloud SQL for PostgreSQL for our PostgreSQL databases and Google Cloud Memorystore for Redis . For our CI/CD pipeline, we are using CircleCI and Google Cloud Build to deploy applications managed with Helm . The new infrastructure is managed with Terraform .

Read the blog post to go more in depth.

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Russel Werner
Lead Engineer at StackShare · | 7 upvotes · 279.3K views

We began our hosting journey, as many do, on Heroku because they make it easy to deploy your application and automate some of the routine tasks associated with deployments, etc. However, as our team grew and our product matured, our needs have outgrown Heroku. I will dive into the history and reasons for this in a future blog post.

We decided to migrate our infrastructure to Kubernetes running on Amazon EKS. Although Google Kubernetes Engine has a slightly more mature Kubernetes offering and is more user-friendly; we decided to go with EKS because we already using other AWS services (including a previous migration from Heroku Postgres to AWS RDS). We are still in the process of moving our main website workloads to EKS, however we have successfully migrate all our staging and testing PR apps to run in a staging cluster. We developed a Slack chatops application (also running in the cluster) which automates all the common tasks of spinning up and managing a production-like cluster for a pull request. This allows our engineering team to iterate quickly and safely test code in a full production environment. Helm plays a central role when deploying our staging apps into the cluster. We use CircleCI to build docker containers for each PR push, which are then published to Amazon EC2 Container Service (ECR). An upgrade-operator process watches the ECR repository for new containers and then uses Helm to rollout updates to the staging environments. All this happens automatically and makes it really easy for developers to get code onto servers quickly. The immutable and isolated nature of our staging environments means that we can do anything we want in that environment and quickly re-create or restore the environment to start over.

The next step in our journey is to migrate our production workloads to an EKS cluster and build out the CD workflows to get our containers promoted to that cluster after our QA testing is complete in our staging environments.

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Blog Posts


CircleCI's Features

  • Language-Inclusive Support
  • Custom Environments
  • Flexible Resource Allocation
  • SSH Or Local Builds For Easy Debugging
  • Improved Caching
  • Unmatched Security
  • Parallelism
  • Insights

CircleCI Alternatives & Comparisons

What are some alternatives to CircleCI?
In a nutshell Jenkins CI is the leading open-source continuous integration server. Built with Java, it provides over 300 plugins to support building and testing virtually any project.
Travis CI
Free for open source projects, our CI environment provides multiple runtimes (e.g. Node.js or PHP versions), data stores and so on. Because of this, hosting your project on means you can effortlessly test your library or applications against multiple runtimes and data stores without even having all of them installed locally.
Codeship runs your automated tests and configured deployment when you push to your repository. It takes care of managing and scaling the infrastructure so that you are able to test and release more frequently and get faster feedback for building the product your users need.
Azure DevOps
Azure DevOps provides unlimited private Git hosting, cloud build for continuous integration, agile planning, and release management for continuous delivery to the cloud and on-premises. Includes broad IDE support.
Concourse's principles reduce the risk of switching to and from Concourse, by encouraging practices that decouple your project from your CI's little details, and keeping all configuration in declarative files that can be checked into version control.
See all alternatives

CircleCI's Followers
6510 developers follow CircleCI to keep up with related blogs and decisions.