When the testers actually involves in testing in sdlc?

Testers are involved in the Software Development Life Cycle (SDLC) primarily during the testing phase, which follows the development phase. However, their involvement begins earlier during the requirements gathering and design phases, where they provide input on testability and identify potential issues. This early engagement helps ensure that the final product meets user expectations and functional requirements. After development, testers conduct various testing types, such as unit, integration, system, and user acceptance testing, to validate the software before its release.