Accessibility modifications are required for individuals with situational, temporary, or permanent impairments to properly interact with web applications. Incorporating accessibility guidelines, such as the Web Content Accessibility Guidelines (WCAG), into software development, along with the software development life cycle and other paradigms, poses challenges. The linear progression of steps in a conventional software development process leads to the identification of problems at a later stage because testing is typically conducted toward the end. Limited attention to accessibility until the final development phase results in prolonged efforts, increased resource allocation, and higher expenses to address accessibility issues. Consequently, numerous software applications remain inaccessible to users with impairments. This study focuses on a Shift Left-based model to improve accessibility in the software development process. Employing the Shift Left a11y Model that emphasizes early integration for accessibility and coupling it with the Extreme Programming Development Life Cycle would enhance the integration of various testing practices and facilitate the development of software that is accessible to all users, including those with impairments.