The Software Development Lifecycle (SDLC) is a structured approach to software development that outlines the stages of planning, designing, testing, deploying, and maintaining software applications.
SDLC provides a systematic process for developing high-quality software, ensuring that it meets both the functional and non-functional requirements of the users. Furthermore, SDLC helps manage project complexity, deliver on time, and stay within budget.
Here is an overview of the six (6) different SDLC phases.
Overview of the typical Software Development Lifecycle stages
1. Planning and Requirements Gathering.
This is stage where you define the project’s goals, scope, deliverables, and constraints. This phase ensures a clear understanding of the user needs and business objectives. To have a clear understanding, it is important to:
- conduct interviews with stakeholders (clients, users, etc.)
- gather functional and non-functional requirements
- create a project plan, including timelines, resources, and budgets
- define high-level system architecture and technology stack
Doing these helps to have deliverables such as (i) the requirements specification document (functional and non-Functional requirements), and (ii) project plan and schedule.
2. System Design.
This is stage where you create a blueprint for the software architecture. This phase involves designing both the high-level and low-level system architecture. It is important to:
- define system components, modules, and their interactions
- specify details about database schema, APIs, user interface, algorithms, and any technical considerations
- create wireframes or mockups for the user interface
Doing these helps to have deliverables such as (i) the system design document, and (ii) a prototype or a User Interface (UI) or User Experience (UX) design.
3. Implementation.
This is stage where you develop the actual software application based on the design documents. The code is written, and the functionality is implemented. It is important to:
- write the code in the chosen programming languages
- create and configure databases
- implement user interfaces and backend logic
- follow coding standards, best practices, and version control
Doing these helps to have deliverables such as (i) software source code, (ii) database schemas and tables. and (iii) unit tests (if applicable).
4. Testing.
This is stage where you ensure that the software is free of defects, free of security issues and that it meets the specified requirements. Testing ensures the quality, security and reliability of the software. It is important to:
- test individual components or functions
- ensure different modules work together as expected
- verify that the system works as a whole
- verify that the software is not prone to data loss, malware, hacking and other security vulnerabilities
- have end-users test the system to ensure it meets their needs and requirements,
- check for performance bottlenecks, and re-test after bug fixes or code changes
Doing these helps to have deliverables such as (i) test plans, (ii) test cases and results, and (iii) bug reports.
5. Deployment.
This is stage where you make the software available to users, either in a production environment or a live setting. It is important to:
- deploy the application to the production server or cloud environment
- configure servers, databases, and other dependencies
- perform a final round of testing to confirm the deployment is successful
- train users (if necessary) and provide documentation for end users
Doing these helps to have deliverables such as (i) the deployed software, (ii) user documentation, and (iii) training materials.
6. Maintenance and Support.
This is stage where you provide ongoing support and make any necessary updates to the software after it is live. This phase ensures that the software remains functional and secure over time. It is important to:
- monitor software performance and address any issues
- fix bugs that were not discovered during earlier testing
- implement software updates or enhancements based on user feedback
- handle ongoing technical support and maintenance tasks
Doing these helps to have deliverables such as (i) maintenance updates, (ii) bug fixes, and (iii) new features (in future releases).
Now that you have an understanding of the different stages. Which SDLC model is best suited for your software development project? To answer this, you need to know the different models and when to choose either.
Choosing a SDLC Model
There are different Software Development Lifecycle models. These are either Waterfall, Agile, Spiral, V-Model, or Iterative. All these SDLC models generally include the six (6) core stages you went through earlier.
To explain the different choices better, the table below present the distinctions between the different SDLC models.
Overview, phases, pros, cons, and suitability of the different SDLC Models
This table briefly explains all you need to know about the different SDLC models and when to choose either.
| Model | Overview | Phases | Pros | Cons | Suitability |
|---|---|---|---|---|---|
| Waterfall | A linear and sequential model where each phase must be completed before the next one begins. | Requirements → Design → Implementation → Testing → Deployment → Maintenance. | Simple, easy to understand, and effective for small projects with clear, fixed requirements. | Inflexible, hard to go back to earlier stages, not ideal for projects with evolving requirements. | It’s best suited for projects with well-defined requirements that are unlikely to change. |
| Agile | An iterative and flexible approach where development occurs in small, incremental cycles (called sprints). Each sprint results in a usable piece of software. | Planning → Design → Development → Testing → Deployment → Review → Repeat (iterative). | Adaptable, faster feedback loops, allows for continuous improvement, and encourages collaboration. | Requires active stakeholder engagement, can be difficult to predict timelines and costs, and may lead to scope creep without strong management. | Best for projects where requirements are expected to evolve, and flexibility and quick delivery are important. |
| Spiral | Combines iterative development with a risk management approach. It allows for incremental releases while also addressing risks through frequent evaluation. | Planning → Risk Analysis → Engineering → Testing → Evaluation → Repeat. | Focus on risk management, flexibility, and iterative refinement. | Can be complex to manage, requires skilled project management, and can be time-consuming. | Ideal for large, complex projects with high risk and a need for frequent assessment. |
| V-Model (Verification and Validation) | A variation of the Waterfall model where each development phase has a corresponding testing phase. The focus is on validation and verification throughout the lifecycle. | Requirements → Design → Coding → Unit Testing → Integration Testing → System Testing → Acceptance Testing. | Clear focus on validation, early detection of defects, good for projects with well-defined requirements. | Like Waterfall, it’s inflexible and not ideal for changing requirements. | Good for projects that need strict validation and verification, such as medical software or safety-critical systems. |
| Iterative | The development process is broken down into smaller iterations, where each iteration delivers a part of the functionality. The project grows with each iteration. | Requirements → Design → Implementation → Testing → Deployment → Repeat. | Flexibility, early and continuous delivery of functionality. | Less predictability in scope and timelines, can be resource-intensive. | Effective for projects that require gradual refinement and incremental releases. |
In conclusion, the Software Development Lifecycle (SDLC) provides a structured process for building software applications, ensuring the project meets its goals while staying within scope, time, and budget constraints. Understanding the different SDLC models and phases helps organizations select the most suitable approach for their projects, whether they follow a traditional Waterfall approach or an Agile, iterative development process. By adhering to the SDLC, development teams can ensure quality, efficiency, and user satisfaction in the software they create.
