The V-model is a software development lifecycle model where each phase of the development process is validated by an equivalent phase of testing. It emphasizes testing at each development stage. In the V-model, testing begins during the requirements analysis phase, and each subsequent development phase is tested before moving further down the V, and development and testing phases occur in parallel. The benefits of the V-model include preventing faults, avoiding downward flow of defects, lower rework costs, improved quality and risk management.