Alternate development of programmers? ? ?

     What is the alternate development of programmers, I really don't understand this! ! ! Bosses who don't understand technology assign work. Develop an e-commerce platform, and access two payment methods by the way. I am the only one in the back-end and front-end, and there is no technical director. Which god will answer. For a small company, there are only three developers in total. The other two are doing mobile development. In addition, I have only one year of work experience. Although I can do this work, but ah, are the two colleagues on the mobile terminal going on vacation for half a year? They'll come to work when I'm done. Ask for answers! !

    What is alternate development! ! !