10 Differences Between sdlc and stlc


SDLC vs. STLC: Understanding the Differences

What is SDLC?

Software Development Life Cycle (SDLC) is a systematic approach to develop software applications that includes a set of well-defined steps or phases. It provides a framework for developers and project managers to plan, build, test, and deploy software efficiently.

Examples of SDLC

Examples of SDLC methodologies include Waterfall, Agile, Scrum, and Spiral.

Uses of SDLC

The primary uses of SDLC are:

  • Ensuring thorough software planning and requirement gathering.
  • Delivering high-quality software with reduced risks.
  • Managing software development projects effectively.
  • Providing a structured and disciplined approach to development.

What is STLC?

Software Testing Life Cycle (STLC) is a set of testing activities and processes performed to ensure the quality and reliability of software. It involves planning, designing, executing, and evaluating tests to identify defects or issues within the software.

Examples of STLC

Examples of STLC phases include Test Planning, Test Design, Test Execution, and Test Closure.

Uses of STLC

The primary uses of STLC are:

  • Ensuring that software meets functional and non-functional requirements.
  • Identifying and eliminating defects or bugs before software deployment.
  • Improving the overall quality, performance, and security of software.
  • Providing confidence in the software’s reliability and proper functioning.

Differences between SDLC and STLC

Difference Area SDLC STLC
Approach Focuses on software development and implementation. Focuses on software testing and quality assurance.
Primary Goal To deliver a fully functional software product. To ensure the quality and reliability of the software.
Phases Includes planning, coding, testing, and maintenance. Includes test planning, test design, test execution, and test closure.
Activities Requirements analysis, design, coding, and deployment. Test planning, test case design, test execution, and defect reporting.
Role Focus Developers, project managers, and software architects. Testers, quality assurance engineers, and test managers.
Timing SDLC initiates before STLC and continues throughout the entire software development process. STLC starts after the completion of the development phase and continues until the delivery of a defect-free software.
Outputs Software product, documentation, and source code. Test plans, test cases, test execution reports, and defect reports.
Performance Criteria Stability, speed, efficiency, and scalability of the software. Accuracy, completeness, and reliability of the test results.
Process Flow Linear or iterative, depending on the chosen SDLC methodology. Sequential, following a predefined set of activities and test phases.
Deliverables Software application or system ready for deployment. Defect-free software and comprehensive test documentation.


In summary, SDLC and STLC are two essential processes in software development. While SDLC focuses on the development and implementation of software, STLC ensures the quality and reliability of the software through testing and quality assurance activities.

People Also Ask

  • Q: What is the difference between SDLC and STLC?
  • A: SDLC is the process of developing software, while STLC is the process of testing and ensuring software quality.

  • Q: Which comes first, SDLC or STLC?
  • A: SDLC initiates before STLC and continues throughout the software development process.

  • Q: What are the main phases in SDLC?
  • A: The main phases in SDLC include requirements analysis, design, coding, and maintenance.

  • Q: What are the main phases in STLC?
  • A: The main phases in STLC include test planning, test design, test execution, and test closure.

  • Q: What are the key deliverables in SDLC and STLC?
  • A: SDLC delivers a software application ready for deployment, while STLC delivers defect-free software and comprehensive test documentation.

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