What is the V-model?

V-model is a software development lifecycle model that visually resembles the letter "V." It extends the traditional sequential model (Waterfall) by linking development phases with corresponding testing phases.

On the left down the "V" are the design and development stages: requirements, system design, architecture, coding. On the right up are the testing stages: unit, integration, system, acceptance testing.

Each development stage corresponds to its testing stage, ensuring early test planning and improving product quality. For example, requirements correspond to acceptance testing, design to integration testing, and so on.

This model is well-suited for projects with clearly defined requirements and fixed deadlines, where strict verification at each stage is important.