Appsec Knowledge Center

SDLC: The Ultimate Guide To Software Development Lifecycle

SDLC guide

The Software Development Lifecycle (SDLC) lays the foundation for a modern approach to creating software. For that reason, building efficiency, scalability, reliability, and security into the SDLC is critical for any team that wants to build great applications.

This article breaks down everything that organizations need to know about the SDLC, including how it works, which processes factor into the SDLC, security’s role in the SDLC, and best practices for implementing the most efficient SDLC strategies.

What is the Software Development Lifecycle?

Short for Software Development Lifecycle, SDLC is the set of processes that an organization uses to create software. The purpose of the SDLC is to break software development operations into distinct phases that are repeatable and efficient.

SDLC processes

Different people have different opinions about exactly which processes factor into the SDLC and what those processes are called. In general, however, most developers are likely to agree that the SDLC includes the following key phases:


  • Planning: During the planning stage, developers determine what their application needs to do and which resources (in terms of people, tools, and infrastructure) they need to build it.
  • Design: The design phase allows teams to decide which architecture to use for an app, as well as which programming languages or frameworks they’ll code in.
  • Development: Development (also called coding or implementation) is the process of writing the source code for the application.
  • Build: This phase is where the application starts to take shape. Source code turns into executable files and creates the foundation of the application. Developers often build tools and systems to automate this process to ensure consistency in the generation of deployable artifacts in the later stages of development.
  • Testing: After code has been written, teams test it to ensure it meets performance and security requirements.
  • Deployment: Applications that pass testing are deployed into production environments, which means they become available to users.
  • Go-Live: The newly developed, or updated, application is now released for full-scale operation. Here the application transitions out of the testing environment into a live production environment. Maintenance: Maintenance refers to the operations (such as monitoring and incident response) necessary to keep an application running properly once it has been deployed into production.

These SDLC processes occur whenever an organization writes a new application from scratch. In addition, the SDLC is repeated if teams decide to roll out an application update – which they might do to add new features or fix major bugs, for example. Thus, the SDLC is not a one-time operation that applies only to brand-new applications; it’s a recurring practice that helps businesses make applications better over time.

The importance of the SDLC

The SDLC is important because it provides a structured, well-organized approach to the complex process of creating software. In turn, the SDLC delivers several key benefits.

Efficient operations

Developing a modern application could require writing tens of thousands of lines of code, and dozens or even hundreds of programmers might work on it. Given the scale of the work that needs to take place and the large number of people involved, having a tightly organized approach to software development helps ensure that everyone collaborates effectively and keeps the project moving forward.

Reduced risk

In addition, the SDLC is helpful because it reduces the risk of overlooking or skimping on key components of application development. For example, by making testing a systematic step in the software development process, the SDLC ensures that developers thoroughly test code before deploying it into production. Without the SDLC, some teams might approach testing in a more ad hoc manner, increasing the risk that they’d fail to detect major flaws before deploying their code.

Increased development velocity

The SDLC makes it easy to delegate different tasks to different engineers, which helps teams move faster. It also reduces the risks that multiple developers will perform the same work (such as testing code that someone else tested previously), leading to redundancy and development delays.

The role of security in the software lifecycle

Security is not the sole focus of the SDLC, and having a well-organized SDLC is not enough on its own to prevent security problems. However, building security into the SDLC is one critical part of application security.

To ensure that security is a key consideration during the SDLC, teams must integrate security into each of the various processes that take place during the SDLC. Examples of doing so include:

  • Planning: Consider which security tools and personnel will be necessary to secure the application.
  • Design: Choose application designs and languages that help to mitigate security risks.
  • Development: Avoid introducing insecure dependencies into applications, as well as risky practices like hard-coding sensitive data into source code.
  • Build: Utilizing Continuous Integration (CI) can allow for seamless development workflows. Software Composition Analysis (SCA) can detect and address vulnerabilities in open-source software and other third-party components. Incorporating Software Supply Chain Security (SSCS) helps organizations secure all the components in their applications.
  • Testing: Tests that scan applications for security flaws should be integral to the testing phase of the SDLC.
  • Deployment: Avoid security risks during deployment, such as forgetting to turn on additional access controls when an app moves from a testing environment to production.
  • Go-Live/Maintenance: Ensure that security monitoring and response capabilities support the application in production.

SDLC best practices

Every organization’s software development needs are unique, and every team will therefore take a different approach to implementing an SDLC. In general, however, most teams will benefit from SDLC practices like the following:

  • Don’t skimp on planning and design: The planning and design phases are arguably the most important processes in the SDLC because they lay the foundation for everything that happens afterward.
  • Automate, automate, automate: The greater the extent to which teams automate the software lifecycle processes, the more efficient and repeatable those processes become.
  • Align your toolset with SDLC processes: Different parts of the SDLC require different tools; for example, you can use CI servers to help manage source code during development, and test automation frameworks speed in the testing stage. Be sure your team has the tools it needs to manage each part of the SDLC as efficiently as possible.
  • Track SDLC metrics: To measure the effectiveness of your SDLC, track metrics such as how long it takes to complete each stage of the SDLC and how many bugs you fail to catch before deploying an app. Then, compare these metrics to future iterations of your SDLC so you’ll know whether you are becoming more efficient over time.

How Checkmarx can help with your SDLC needs

No matter which type of application you’re building or which risks you face, Checkmarx makes it easy to integrate end-to-end security testing into all relevant stages of the SDLC.

By supporting a range of application security needs – including Static Application Security TestingSoftware Composition AnalysisAPI security management, and more – CheckMarx helps you define a secure application security architecture, by providing an AppSec platform that integrates with and finds security risks in every stage of the SDLC.

You’re welcome to check out our AppSec accelerator turnkey service or learn how to seamlessly integrate Checkmarx into your SDLC running on AWS.