Difference between SDLC and STLC
Last Updated :
12 Jul, 2025
Software Development Life Cycle (SDLC) and Software Testing Life Cycle (STLC) are important parts of software engineering. SDLC has a broad scope; it consists of 6 phases: requirement analysis, design, development, testing, deployment, and maintenance. On the other hand, STLC is a subset of SDLC. It has Focused scope, specially focus on the testing phase of SDLC. The Primary Goal of STLC is to ensure the quality, functionality and reliability of software through various testing activities.
What is Software Development Life Cycle ( SDLC) ?
SDLC is a process followed for software building within a software organization. SDLC consists of a precise plan that describes how to develop, maintain, replace, and enhance specific software. The life cycle defines a method for improving the quality of software and the all-around development process. Software Development Life Cycle (SDLC) is a sequence of different activities performed during the software development process.
SDLC consist of 6 Phases:
- Requirement Analysis
- Software Design
- Software Build
- Testing
- Deployment
- Maintenance
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6 Stages of Software Development Life CycleWhat is Software Testing Life Cycle (STLC)?
The Software Testing Life Cycle (STLC) is a systematic approach to testing a software application to ensure that it meets the requirements and is free of defects. It is a process that follows a series of steps or phases, and each phase has specific objectives and deliverables. The STLC is used to ensure that the software is of high quality, reliable, and meets the needs of the end-users.
STLC consist of 5 Phases
- Test Planning
- Test Case Development
- Test Environment Setup
- Test Execution
- Test Closure
Stages of Software Testing Life Cycle (STLC)Difference between SDLC and STLC
Aspect
| SDLC | STLC |
|---|
Domain
| SDLC is mainly related to software development. | STLC is mainly related to software testing. |
Focus
| Besides development other phases like testing is also included. | It focuses only on testing the software. |
Phases
| SDLC involves total six phases or steps. | STLC involves only five phases or steps. |
Number of Member
| In SDLC, more number of members (developers) are required for the whole process. | In STLC, less number of members (testers) are needed. |
Team Involved
| In SDLC, development team makes the plans and designs based on the requirements. | In STLC, testing team(Test Lead or Test Architect) makes the plans and designs. |
Objective
| Goal of SDLC is to complete successful development of software. | Goal of STLC is to complete successful testing of software. |
End Result
| It helps in developing good quality software. | It helps in making the software defects free. |
Execution
| SDLC phases are completed before the STLC phases. | STLC phases are performed after SDLC phases. |
Maintenance
| Post deployment support , enhancement , and update are to be included if necessary. | Regression tests are run by QA team to check deployed maintenance code and maintains test cases and automated scripts. |
End Result
| Creation of reusable software systems is the end result of SDLC. | A tested software system is the end result of STLC. |
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