What Is Continuous Integration?

Continuous integration (CI) is part of software development best practices and helps development teams organize work into manageable iterations of automated testing and deployment. CI is important for delivering higher quality code faster while providing increased efficiency and less cost than methods that don’t emphasize automation. You can use continuous integration with other methodologies, such as Agile, continuous delivery, and servers that power automation and version control. 

What is continuous integration?

Continuous integration occurs when team members merge code into a central repository which then is automatically built and tested. This practice allows code changes and new features from multiple sources to integrate seamlessly into the main code. 

Development teams working on different project features can work independently using branches created off the main repository of code. This allows them to isolate a workspace and test new ideas without harming the working code. Once new features are ready for integration into the main repository, they merge into the main code. 

At this step, the tools that provide automation, testing, and version control are important to creating continuous integration practices. When a CI server or other CI tool detects new changes, it will compile them, provide testing, package, and deploy the new code into the main working code. 

Benefits of continuous integration

Continuous integration is a DevOps best practice because of the benefits it brings to teams using it. Here are some reasons continuous integration is valuable: 

• Faster iterations: Continuous integration encourages smaller code changes, which are easier to manage and help iterations move faster. Automating parts of the process, such as testing, allows developers to spend more time coding.

• Higher quality code with fewer bugs: Smaller code changes make spotting and fixing bugs and other problems easier. You can also find bugs earlier in the process and use automation to perform more kinds of testing than you would otherwise. Continuous integration also provides immediate feedback on whether or not the changes worked. 

• Able to roll back changes: If something goes wrong and a new update breaks your code somehow, continuous integration allows you to roll back the newest set of changes and immediately revert to a time when the code was working. This is an important feature for software updates so you don’t disrupt people using your software. 

• Reduced expenses: Reduced errors and bugs and increased automation allow development teams to spend more time developing new code and features. In turn, this reduces the cost of creating new features and software. 

What is continuous integration used for?

Continuous integration is used by development teams to provide automated solutions for building, testing, and deploying code and updates to code. Your team can use continuous integration in conjunction with other tools, such as Agile and continuous delivery. 

1. Used with Agile

You can use continuous integration with Agile, a project management methodology that separates tasks into items on a project roadmap. Doing so allows you to organize your team and distribute tasks efficiently. 

Read more: What Is Agile? And When to Use It

2. Automated continuous integration testing

Continuous integration allows solutions for automated testing, including:

• Unit tests

• Integration tests

• Acceptance tests

3. GUI Testing

In graphical user interface (GUI) testing, CI helps streamline and organize testing efforts to free up developers from this tedious task. 

Read more: What Is a GUI?

4. Used with continuous delivery

Continuous integration will often be associated with continuous delivery, sometimes called CI/CD. These terms are sometimes interchangeable but refer to parts of the same process. Continuous integration focuses on building, testing, and compiling the new features into a central repository, while continuous delivery refers to pushing those updates out into working code and delivering smaller updates on a more consistent basis.

CI tools 

The tools you choose to help you implement CI are among the critical parts of continuous integration. Some popular choices include: 

• Jenkins

• TeamCity

• GitLab

• Bamboo

• CircleCI

• TravisCI

• BitBucket Pipelines

• Buildbot

How to get started with continuous integration

DevOps teams use continuous integration. While you can find DevOps engineer positions that exclusively focus on CI/CD, you’ll find that continuous integration is a baked-in feature for teams that work on software development. 

If you want to gain experience in the industry, consider beginning your career as a junior DevOps engineer, junior cloud native software engineer, or junior software engineer. 

Junior DevOps engineer

Average US salary: $92,908 [1]

Job outlook (projected growth from 2022 to 2032): 25 percent [2]

Education requirements: The most common requirement is a bachelor’s degree in computer science, information technology, or a related area of study.

As a junior DevOps engineer, you will work with a team to create code that automates testing and delivery, improve system administration, and perform configuration analysis throughout the organization. As a junior engineer, you may benefit from mentorship and on-the-job training. In some cases, you can start working as a junior engineer while completing education or certification programs. 

Read more: What Does a DevOps Engineer Do? A Career Guide

Junior cloud native software engineer

Average US salary: $111,576 [3]

Job outlook (projected growth from 2022 to 2032): 25 percent [2]

Education requirements: The most common requirement is a bachelor’s degree in computer or information technology or a related area of study

As a junior cloud native software engineer, you will work with a development team on software engineering projects that are cloud native or created and maintained in a cloud environment. Many of the tasks you will be responsible for are similar to those of a junior software engineer, but you will use tools and strategies designed to maximize efficiency in cloud environments. 

Junior software engineer 

Average US salary: $87,057 [4]

Job outlook (projected growth from 2022 to 2032): 25 percent [2]

Education requirements: The most common requirement is a bachelor’s degree in computer or information technology or a related area of study

As a junior software engineer, you will work alongside more experienced engineers to create and maintain software. Depending on your position and the size of your team, you will likely write code in addition to participating in testing, deployment, and more. As a junior engineer, you’ll have the opportunity to access mentorship from more experienced professionals and, in some cases, on-the-job training. 

Read more: What Does a Software Engineer Do?

Learn more

If you’re ready to take the next step and start a career as a junior software engineer, consider earning your IBM DevOps and Software Engineering Professional Certificate on CourseraThis is a 14-course series and it will cover skills in CI/CD, DevOps, cloud native, and more. Upon completion, gain exclusive access to career resources like resume review, interview prep, career support, and more.