Software development is a complex journey. It involves multiple phases, various roles, and collaboration across teams — all aimed at delivering a product that meets business goals and delights users. To navigate this complexity effectively, IT teams rely on two fundamental frameworks: the Software Development Life Cycle (SDLC) and the Software Testing Life Cycle (STLC).
In this training guide, we’ll break down these two cycles, explain their key phases, clarify the responsibilities of different team members, and explore how they work together to produce high-quality software. We’ll also illustrate these concepts with a practical example: building a mobile banking app.
What is the Software Development Life Cycle (SDLC)?
At its core, the SDLC is a systematic, step-by-step process for designing, developing, and maintaining software. Think of it as a roadmap guiding a project from an initial idea all the way to a finished product—and beyond.
Why SDLC Matters
Without a clear process, software projects can quickly become chaotic—requirements get missed, deadlines slip, bugs pile up, and users end up frustrated. The SDLC ensures that:
Requirements are clearly understood and documented.
Work is planned and scheduled effectively.
Designs meet user needs and technical constraints.
Development proceeds methodically and is easy to track.
Testing is integrated to catch defects early.
Deployment happens smoothly.
Ongoing maintenance keeps the software reliable.
By following SDLC, teams improve communication, reduce risks, and deliver software on time and within budget.
Key Phases of the SDLC
Let’s walk through the typical stages most SDLC models include:
1. Requirement Gathering and Analysis
This is where everything begins. Business Analysts (BAs) and product stakeholders collaborate to define what the software should do.
They collect requirements through meetings, interviews, workshops, and document analysis.
The goal is to understand user needs, business rules, and constraints.
For example, if developing a mobile banking app, the BA will gather requirements like “view account balances,” “transfer funds,” and “receive transaction alerts.”
Clear, well-documented requirements form the foundation of a successful project.
2. Planning
Once requirements are clear, project managers and Scrum Masters step in to create a realistic plan.
They estimate timelines, allocate resources, and set milestones.
Priorities are set to ensure the most critical features are delivered first.
Risk assessment and mitigation strategies are established.
In Agile environments, planning happens iteratively, with sprints and backlog grooming.
Effective planning helps the team stay focused and aligned throughout development.
3. Design
In the design phase, software architects and developers craft the technical blueprint.
This includes defining system architecture, data models, interfaces, and technology stacks.
The team decides how components will interact and how to meet non-functional requirements like security and performance.
Using our mobile banking example, the design would specify how the app connects securely to bank servers, manages user authentication, and displays data.
A strong design reduces costly rework later on.
4. Development (Coding)
Here’s where the rubber meets the road. Developers write code based on the design documents.
Programming languages and frameworks are chosen based on project needs.
Code reviews and pair programming improve quality and knowledge sharing.
Continuous integration tools help automate builds and initial tests.
The codebase starts to take shape, transforming ideas into a working product.
5. Testing
Before the software can be released, it must undergo thorough testing to catch defects and ensure quality.
Testers perform functional testing (do features work as expected?), regression testing (do new changes break existing functions?), integration testing (do modules work together?), and performance testing (does the app handle load well?).
Automated tests may be used alongside manual testing.
Any bugs or issues discovered are logged and sent back to developers for fixes.
Testing is critical to deliver reliable software users can trust.
6. Deployment
Once testing is complete and the software meets quality standards, it is deployed to production.
This might involve releasing the app to app stores or deploying web applications to servers.
Deployment strategies like blue-green deployments or canary releases help minimize downtime and risk.
The team monitors the release for issues.
Deployment marks the moment users get to experience the new software.
7. Maintenance and Support
Development doesn’t stop after launch. Ongoing maintenance ensures the software continues to operate smoothly.
Bug fixes, security patches, and performance improvements are delivered regularly.
New features may be added based on user feedback.
Support teams handle user issues and questions.
Maintenance keeps the software valuable and relevant over time.
What is the Software Testing Life Cycle (STLC)?
While SDLC covers the entire development journey, the Software Testing Life Cycle zeroes in on the testing aspect of software quality assurance. STLC defines a structured approach to validating that the software meets requirements and is free of critical defects.
Why STLC is Essential
Testing without a clear process can lead to missed bugs, wasted effort, and low confidence in the product. STLC helps teams:
Plan and organize testing activities efficiently.
Define clear objectives and success criteria.
Track defects and test coverage systematically.
Communicate test results effectively to stakeholders.
By following STLC, teams increase the likelihood of delivering robust software that meets client expectations.
Key Phases of the STLC
Here are the typical stages involved in the testing life cycle:
1. Requirement Analysis
Testers review the project’s requirements to identify what needs testing.
They determine testable requirements and identify potential gaps or ambiguities.
For the banking app, testers would identify scenarios like “login functionality,” “fund transfers,” and “view transaction history.”
A thorough analysis ensures tests align with business needs.
2. Test Planning
A Test Lead or QA Manager creates a test plan defining:
Scope and objectives of testing.
Testing strategies and methodologies.
Resource allocation (number of testers, tools, environments).
Schedule and milestones.
The plan sets expectations and guides the entire testing effort.
3. Test Case Development
Testers write detailed test cases that specify:
What to test.
Input data.
Expected outcomes.
Steps to execute the tests.
For example, a test case might be: “Verify that a user can log in with valid credentials and receives an error message with invalid credentials.”
Clear, well-documented test cases improve test coverage and reproducibility.
4. Test Environment Setup
Preparing the testing environment involves configuring hardware, software, and network settings to mimic production conditions.
This includes setting up devices, databases, servers, and test tools.
For mobile apps, testers might set up both iOS and Android devices.
A stable environment is critical for accurate test results.
5. Test Execution
Testers run the test cases, either manually or using automation tools.
They log any defects found and report progress.
Defects are prioritized and sent back to developers for resolution.
Test execution validates whether the software behaves as intended.
6. Test Closure
After all planned tests are complete, the team reviews results.
Test summary reports are prepared.
Lessons learned and process improvements are documented.
The team confirms all critical defects are resolved or accepted.
Test closure wraps up the testing phase and feeds into release decisions.
Roles and Collaboration in SDLC and STLC
Successful software delivery requires smooth collaboration across multiple roles, each with distinct responsibilities but shared goals.
Developers
Write, review, and maintain the codebase.
Fix defects identified by testers.
Collaborate with BAs and POs to understand requirements.
Participate in design discussions.
Business Analysts (BAs)
Bridge the gap between clients and technical teams.
Gather, clarify, and document requirements.
Help translate business needs into user stories or specifications.
Facilitate communication to reduce misunderstandings.
Product Owners (POs)
Represent the customer’s interests.
Prioritize features and backlog items.
Make trade-off decisions between scope, time, and quality.
Ensure the team delivers maximum value.
Scrum Masters / Project Managers
Facilitate Agile ceremonies and workflow.
Remove impediments to team progress.
Help the team adhere to processes.
Coordinate communication between stakeholders.
Testers / QA Engineers
Develop and execute test plans and cases.
Identify and report defects.
Ensure the software meets quality standards.
Work closely with developers and BAs to clarify issues.
Example: Developing a Mobile Banking App
Let’s bring this all together with a practical example. Imagine your company is building a mobile banking app to help customers manage their finances on the go.
SDLC in Action
Requirement Gathering: The BA meets with the bank’s product team to understand the features needed—checking balances, transferring funds, paying bills, and transaction history.
Planning: The Scrum Master and PO prioritize these features and set a sprint schedule.
Design: Architects design a secure, scalable app architecture ensuring data privacy.
Development: Developers write code in Java (for Android) and Swift (for iOS) to build the app.
Testing: QA engineers test login functionality, transaction workflows, and security features.
Deployment: The app is released on Google Play and the Apple App Store.
Maintenance: After launch, the team monitors user feedback, fixes bugs, and rolls out updates.
STLC in Action
Requirement Analysis: Testers identify scenarios like valid and invalid logins, fund transfers, and notification alerts.
Test Planning: The test lead creates a plan emphasizing security and usability testing.
Test Case Development: Detailed test cases are written, such as “Verify that the app locks after 5 minutes of inactivity.”
Environment Setup: Testers configure devices with different OS versions to ensure compatibility.
Test Execution: Tests run manually and automatically; defects like crashes during transfer are logged.
Test Closure: The team reviews test results, confirms fixes, and signs off before release.
Summary: Why SDLC and STLC Matter
SDLC guides the overall software creation process, from idea to deployment and beyond. It helps teams build the right product in a structured way.
STLC focuses on the testing activities needed to verify that the software works correctly and meets quality standards.
Both cycles are interdependent and require close collaboration among developers, testers, BAs, POs, and Scrum Masters.
Understanding these cycles helps IT professionals contribute effectively, anticipate challenges, and deliver valuable software solutions.
Tips for IT Teams
Engage early and often. BAs and testers should be involved from the start to catch gaps early.
Keep communication clear. Use documentation, meetings, and tools to keep everyone aligned.
Automate where possible. Automate repetitive tests to save time and improve consistency.
Embrace Agile principles. Iterative development and continuous feedback improve quality and responsiveness.
Review and improve. Use retrospectives and test closure reports to refine your processes.
By mastering the SDLC and STLC, your IT team will be well-equipped to deliver software that meets user needs, performs reliably, and stands up to the demands of today’s fast-paced tech landscape.