DevOps Engineer (or simply devops) is a specialist who participates in all stages of the product life cycle, ensures close cooperation between development teams to optimize their work processes and, as a result, helps to reduce the hour in which a software product will reach the end user.
A web developer is a multidisciplinary specialist who deals with the software-administrative and visual part of a website, program or mobile application. Such a developer is usually called a full-stack developer. By the way, the developer who develops the software and administrative part is called a back-end developer, and the developer who develops the visual part of the site, program or application is called a front-end developer. But most often, these specialists are called backend or frontend for short.