Software-as-a-Service businesses are under constant pressure to iterate on their products. Competition is fierce and customers can migrate to alternatives with minimal friction. To be competitive SaaS businesses must deploy secure and reliable code into production regularly. Continuous integration enables businesses to move quickly, iterate over short development cycles, and be responsive to customer needs and the competitive landscape.
Traditional development models focus on major releases that may take place months apart. Developers work on new features and codebase changes that are integrated into the product before release. The “integration” phase was itself time-consuming and complex, often delaying releases and demanding rounds of testing and bug-fixing before the software could be released.
In contrast, continuous integration focuses on making incremental changes to the codebase, often several times a day. The developer lowers the cost in time and effort of code changes by committing code frequently. It is easier to integrate small changes focused on a limited area of the codebase than large-scale changes that may touch thousands of lines of code across hundreds of files.
Continuous integration is only possible because much of the work can be automated. Version control systems make it easy to integrate small changes into a codebase and collaborate on code review. But it is automated testing that makes continuous integration a useful tool. Without automated testing using server hosted testing platforms like Jenkins or Selenium, the burden of manual testing for each small commit would overshadow any efficiency gains.
Continuous integration has been widely adopted by the SaaS industry. Facebook, Google, and hundreds of other companies use continuous integration because they need to move fast and get code into production quickly. Facebook famously makes changes to its production applications several times a day.
The most important benefits of continuous integration include:
- Fast development-testing-production cycles — With continuous integration, code can be written, tested, and put into production on a much shorter timeline.
- Developer efficiency — Developers should spend their time adding features and improving the codebase, not on long and unproductive periods of integration, a situation that commonly arises with large integrations.
- Code quality — Test-driven development, unit testing, and automated integration testing ensures that all code is tested for unintentional consequences before being integrated into the codebase.
- Testing in a standardized environment — Automated testing puts an end to the once common refrain “But it worked on my development machine!”. When all testing is done in an automatically deployed environment that matches the production environment, developers can be confident that there won’t be any surprises when code hits production servers.
- Repeatable processes — Automated processes can be designed to embody best practices: no one will be able to “accidentally” slip code into production without testing because all code goes through standardized and automated processes.
Continuous integration is an essential part of modern Software-as-a-Service development and is key to a development and deployment process that can respond to the needs of users, the market, and the business.