Software Development Life Cycle(SDLC) Vs Software Test Life Cycle(STLC)

Software Development Life Cycle(SDLC) Vs Software Test Life Cycle(STLC)

Key Difference between SDLC and STLC

SDLC defines all the standard phases involved during the software development process, whereas the STLC process defines various activities to improve product quality.

SDLC is a Development Life Cycle, whereas STLC is a Testing Life Cycle.

In SDLC, the development team creates the high and low-level design plans, while In STLC, the test analyst creates the System Integration Test Plan.

In SDLC, real code is developed, and actual work takes place as per the design documents, whereas in STLC, the testing team prepares the test environment and executes test cases.

The SDLC life cycle helps a team complete the software’s successful development, while the STLC phases only cover software testing.

What SDLC?

The Software Development Life Cycle (SDLC) defines all the standard phases of software development. SDLC Life Cycle is a process of developing software in a phased manner in the following order

Requirements Gathering
Design the software
Build the Software

Each stage has definite entry and exit criteria along with deliverables.

What is STLC?

Software Testing Life Cycle (STLC) is the testing process that is executed in a well-planned manner. In the STLC process, various activities are carried out to improve the quality of the product. However, STLC Phases only deal with testing and detecting errors, not development.

Different companies define different phases in STLC. However, the generic Software Test Life Cycle has the following stages.

Requirement Analysis
Test Planning
Test Development
Test Environment Setup
Test Execution & Closure

Why Use SDLC?

Here are some prime reasons for using the SDLC method:

It aims to produce a high-quality software system that helps you meet customer expectations.

A formal review is created after the completion of every stage that provides optimum management control.
SDLC helps you to create considerable system documentation

It produces many intermediate products that can be reviewed to verify whether they can meet the user’s needs and are according to the stated requirement.

SDLC helps you to ensure that system requirements can be traced back to stated business requirements
Every phase has a specific deliverable, entry, and exit criteria.

Development stages go individually, which is ideal for small or mid-sized projects where requirements are precise.


Here are Important reasons for using the STLC method:

STLC helps make the testing process more sophisticated, consistent, and effective

You can include milestones and deliverables for each step of the project

Easy to understand and implement even if the model is expanded to various levels

Time constraints are strongly built into project formulation

Each module of the project is tested before the beginning of the other module

The requirement of the specific project is measured against the actual result


Software development life cycle(SDLC) and Software Testing Life cycle(STLC) go parallelly.

SDLC (Software Development Life cycle)STLC (Software Test Life Cycle)
SDLC is Software Development LifeCycle, it is a systematic approach to develop a software.The process of testing a software in a well planned and systematic way is known as software testing life cycle(STLC).
Requirements gatheringRequirements Analysis is done is this phase, software requirements are reviewed by test team.
DesignTest Planning, Test analysis and Test design is done in this phase. Test team reviews design documents and prepares the test plan.
Coding or developmentTest construction and verification is done in this phase, testers write test cases and finalizes test plan.
TestingTest Execution and bug reporting, manual testing, automation testing is done, defects found are reported. Re-testing and regression testing is also done in this phase.
DeploymentFinal testing and implementation is done is this phase andfinal test report is prepared.
MaintenanceMaintenance testing is done in this phase.