Whether you’re just starting out in software testing or have some experience in development, you’ve probably come across the terms SDLC and STLC. While they may sound similar, they serve different but interconnected purposes in the software development process. In this blog post, we’ll break down both concepts, their phases, and provide simple examples to help you understand their roles more clearly.
What is SDLC?
SDLC stands for Software Development Life Cycle. It is a structured process used by development teams to design, develop, test, and deploy software applications.
SDLC Phases:
- Requirement Gathering and Analysis
Stakeholders define the scope and requirements of the project. Example: A client wants a mobile app to track daily expenses. Requirements include login, dashboard, charts, and reports. - Design
Architects and designers create the technical design and system architecture. Example: A wireframe of the app, database schema, and API structure is created. - Implementation (Development)
Developers start coding based on the design documents. Example: Developers write code for login functionality, dashboards, and charts. - Testing
The software is tested to ensure it meets all requirements. Example: Testers check if users can log in and if the expense summary is displayed correctly. - Deployment
The finished product is released to the market or internal users. Example: The app is published on the App Store or Google Play. - Maintenance
Post-deployment, the app is monitored for bugs or enhancement requests. Example: Adding new features based on user feedback.
What is STLC?
STLC stands for Software Testing Life Cycle. It defines the testing process and steps taken to ensure the software is free of defects and works as expected.
STLC Phases:
- Requirement Analysis
Testers review requirements and identify testable aspects. Example: From the “expense app” requirements, testers identify that login must support email/password and Google sign-in. - Test Planning
Define scope, approach, resources, and schedule for testing. Example: Test manager decides to use manual testing for login and automation for dashboard verification. - Test Case Design
Testers write test cases and prepare test data. Example: Write test cases like “Login with valid credentials”, “Login with invalid password”, etc. - Test Environment Setup
Prepare hardware and software conditions for testing. Example: Install the app on Android and iOS devices with proper user roles. - Test Execution
Run test cases and log results. Example: Execute login test cases and report any bugs (e.g., app crashes on incorrect login). - Test Closure
Document and share test summary and lessons learned. Example: Prepare a test summary report showing 95% of test cases passed, with 3 open bugs deferred to the next sprint.
SDLC vs STLC: Key Differences
| Aspect | SDLC | STLC |
|---|---|---|
| Focus | Software development | Software testing |
| Participants | Developers, Architects, Business Analysts | QA/Testers |
| Output | Working software | Verified and validated software |
| Includes Testing? | Yes, as one phase | Entire life cycle focused on testing |
How They Work Together
STLC is a subset of SDLC. While SDLC covers the entire software development process, STLC focuses only on the testing part.
Think of SDLC as the full movie production process, and STLC as the post-production editing phase. Both are essential to release a quality film (or software).
Final Thoughts
Understanding the difference and relationship between SDLC and STLC is crucial for software professionals. While developers focus on building the product, testers ensure it meets quality standards. Both life cycles play complementary roles in delivering high-quality software that meets user expectations.
Bonus Tip:
Use tools like Jira, TestRail, or qTest to manage SDLC and STLC processes more efficiently.
Have questions or want to share your experience with SDLC/STLC? Drop a comment below!
