Difference between SDLC & STLC

Difference between SDLC and STLC

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Hello friends, in this post, we are going to study the difference between SDLC and STLC. Along with that, we will see the mapping between their different phases. So, let’s begin with this article on SDLC vs STLC, starting with their definitions first.

What is SDLC?

SDLC stands for Software Development Life Cycle. It describes the various phases involved in the software development process. With the help of SDLC, we can create software applications in a well-defined and systematic way.


The different phases of the Software Development Life Cycle are-

  • Requirement Gathering and Analysis – In this phase, all the requirements are gathered and analyzed for their feasibility.
  • Designing – In this phase, the requirement specifications are converted into design specifications.
  • Coding/Implementation – Actual coding is done here.
  • Testing – This phase involves testing the software product.
  • Deployment – The software is deployed to production for the end user.
  • Maintenance – Due to changes in the environment and for continuous improvement maintenance is required.

What is STLC?

STLC stands for the Software testing life cycle. It refers to all these activities performed during the testing of a software product. Basically, it provides a sequence of activities performed to ensure the quality of the software application.

Difference between SDLC and STLC

The different phases of the Software Testing Life Cycle are-

  • Requirement Analysis – In this phase, the high-level analysis of the requirements is done.

  • Test Planning – In this phase, a test strategy and approach are defined.

  • Test Case Development – The test cases are created in this phase.

  • Test Environment Setup – Here, the test environment is created in which the test execution will be performed.

  • Test Execution – Test cases are executed and defects are logged for the failed tests.

  • Exit Criteria Evaluation and Reporting – Based on the agreed-upon exit criteria, the testing activities are marked as complete.

  • Test Closure – A test closure document is prepared which contains all the testing activities performed and the bugs found. This phase marks the formal closure of the testing phase.

Mapping of SDLC and STLC Phases

As we know that development and testing are carried out parallelly. So, now let’s see the mapping between the phases of SDLC and STLC.

Requirements GatheringRequirement Analysis-
The requirements documents are analyzed and validated and the scope of testing is defined.
DesigningTest Planning, Analysis, and Design-
Defining test specifications, analysis, and reviewing of requirement documents, risk analysis reports, and other design specifications.
CodingTest Case Development, Test Environment Setup-
Involves the test case creation, test data and environment setup.
TestingTest Execution-
Involves manual and automated test case execution and result logging.
DeploymentExit Criteria Evaluation, Reporting, and Test Closure-
Involves checking if all the project deliverables are delivered, archiving the test ware, test environment, and documenting the learnings.
MaintenanceMaintenance testing-
It is the testing required after an upgrade, correction or any change in the software under maintenance.

That’s all I have in this post on SDLC vs STLC. Feel free to ask any questions in the comments. Check the below section for the difference between some other commonly confused terms.

More Difference Between

Manual vs Automation TestingSmoke vs Sanity Testing
White-box vs Black-box TestingSystem vs Integration Testing
Verification vs ValidationQuality Assurance vs Quality Control
SDLC vs STLCTest Plan vs Test Strategy
Test Case vs Test ScenarioAgile vs Waterfall Model
Agile vs Scrum MethodologyREST vs SOAP Web Service
Web Application vs Desktop ApplicationWeb Service vs Website
Assert vs VerifyError, Defect, Fault, Failure & Bug

4 thoughts on “Difference between SDLC and STLC”

  1. Hi Kuldeep,

    I have find your page very helpful and informative. Thank you so much on this.
    Just want to ask, we are now currently creating processes and guide for SIT and Acceptance Testing. I have also checked your System vs Integration Testing. Do you have a blog or article pertaining the deliverables need for SIT, Integration and Acceptance Testing i.e Test Plan, Test Strategy etc?

    Thank you.

  2. Hi Team,

    Good Morning!

    I’ve noted one discrepancy. If we click on the Quick link: Difference b/w: Test Plan & Test Strategy in the Navigation Menu on the left, it opens the SDLC vs STLC page. I tried it multiple times.

    Therefore, please validate the same & rectify if it’s an actual issue!


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