The software development lifecycle (SDLC) looks different for every team, but standard methodologies have emerged and evolved to help teams plan, test, and maintain projects with consistency and accuracy. These methodologies offer a clear approach to software development, ensuring each phase of development -- from initial design to post-deployment maintenance -- executes effectively.
In recent years, adding security into these SDLC methodologies has created challenges, but both the methodologies and security solutions have evolved to address the challenge.
SDLC models, or methodologies, are structured processes that guide software development and maintenance. These project management strategies outline processes for delegation, reporting, and quality assurance, helping teams reach project goals in the most streamlined way possible.
Let's review seven popular SDLC types and how they work.
Agile is one of the most popular SDLC methodologies, emphasizing iterative development, flexibility, and organization-wide collaboration. Its responsiveness to change makes it stand out.
Agile structures projects into sprints: time-boxed iterations that often last between 1-4 weeks. Each sprint could include elements of project design, development, testing, and deployment, meaning most development steps happen simultaneously. This offers more opportunities to evaluate processes and implement small, incremental improvements when necessary.
The Agile model includes core teams of developers, testers, and product owners, though stakeholders (like business managers and project managers) are also actively involved in aligning each sprint's main objectives with business needs.
Application security solutions that are automated and embedded into developer workflows are a must for Agile teams.
The Waterfall model is a linear, sequential approach to software development, dividing the SDLC into six distinct phases:
Each phase must be completed before the next, creating a structured workflow from initial project conception to delivery. Think of the Waterfall methodology as Agile's opposite. Its straightforward process makes projects generally easy to manage and understand, and it's best for those with clear, well-defined requirements and a low probability of change.
Although it used to be a popular choice, many organizations have moved past the Waterfall method for more adaptable and flexible processes. As development cycles increased in pace and application security emerged as a priority, this type of development has struggled to keep up. When security is a discrete step before deployment, it can become a bottleneck and cause expensive and time-consuming development re-work.
DevOps marries development (Dev) and operations (Ops) teams to improve collaboration, automate different steps, and accelerate the software delivery process. This methodology spans the entire SDLC, including everything from project planning to post-deployment monitoring.
Continuous integration (CI) and continuous delivery (CD) -- processes that facilitate quick release and improvement -- are key to DevOps methodology. Because of this, DevOps is closely related to Agile but builds on it by integrating operations and promoting continuous feedback loops throughout the development process.
DevOps' qualities help you deliver higher-quality, error-free software without compromising development speed or release frequency. There's also a culture of shared responsibility, where all parties involved work together throughout the entire SDLC. This contrasts with other methodologies, where teams often operate in silos.
In recent years, many enterprises have evolved from DevOps to DevSecOps, where the development cycle bakes in security personnel and solutions from the start, rather than tacking it on at the end and slowing things down.
Scrum is an Agile-based methodology that facilitates iterative, incremental software development. Like Agile, Scrum structures work into sprints, each lasting between 2-4 weeks. Each one includes:
This methodology relies on a Scrum team -- a self-organizing, cross-functional group responsible for executing sprints. The team includes:
Like Agile, Scrum prioritizes adaptability, continuous feedback, and the ability to respond to changes quickly. But its cyclical structure and sprint retrospectives give you more opportunities to review and reassess sprint processes. It's ideal for projects that require consistent progress and stakeholder involvement.
Lean focuses on maximizing value and minimizing waste, both in time and resources. Pulling core values from Lean manufacturing, like optimized workflows, reduced cycle times, and team empowerment, Lean development has one major goal: continuous improvement.
Lean development has several stages, which include defining value, mapping value streams, creating flow, and establishing pull. Similar to Scrum and Agile, this framework also uses an iterative approach to development, prioritizing continuous improvement and responsiveness to change -- all while aiming to reduce bottlenecks and waste. But while it shares similarities with other methodologies, Lean stands out for eliminating activities that offer little or no value to the end product.
Kanban is a visual SDLC methodology focused on CD and flow. It's a visual board divided into columns, each representing a different stage of work: "To Do," "In Progress," and "Done." Development tasks move across these columns as they progress, giving teams and relevant stakeholders a clear, real-time overview of every project element.
While Kanban spans typical SDLC phases, like project requirements, development, and deployment, it emphasizes incremental improvements instead of fixed, time-boxed iterations. Kanban also doesn't prescribe specific iteration periods. Instead, teams make gradual, ongoing improvements to processes as they work rather than within a specific period, adding more flexibility.
The Spiral model combines iterative development and systematic risk management. Structured as a series of repeating cycles called "spires," Spiral has four key development stages: planning, risk analysis, engineering, and evaluation. During each one, you identify the cycle's objectives, assess potential security risks, and develop product or feature prototypes -- all while gathering feedback along the way.
Part of what makes the Spiral methodology so unique is its emphasis on security. During each spire, teams actively identify risks, anticipate their impact, and build out mitigation strategies before proceeding with development. This proactive approach keeps expensive, security-breaching errors from making it into production.
Regardless of which type of SDLC methodology you choose, keep security at the forefront of your development practice without slowing it down. Legit Security's adaptive, flexible approach to application security helps you at every stage.
If you're ready to take security seriously, you might consider a DevSecOps approach, which integrates security into every step of the DevOps process. With Legit Security, you can embed controls and automated checks throughout the SDLC, meaning even the fastest-moving development processes won't be slowed by security, supporting a DevSecOps approach.
Book a demo to see how you can embed Legit Security within your development workflow.