SPOF can be applied to the ERP company themselves. Services fail all of the time. DockerHub failed on Friday with their container API which you could argue made it impossible to know the outcome of your builds but you could still get by and pull your containers after pushing repositories. As someone who understands how I can be a single point of failure I make sure to ask for raises within reason and since I love what I do usually means at market rate. It's not like I am holding a company hostage by knowing what value I bring. Not everyone is of the persuasion of extorting their employer due to what their perceptive value is. My time is valuable but not so valuable that I price myself out of a market by my ego. To add to the backstory I have been an employee of the company for the last 4 years with never an intention of leaving nor an intention of taking advantage of any perceived leverage. Some people will disagree and say that I should advocate for more at all times. My perception is either I start my own company and build my ideas/imagination or I keep doing what I do. Why does everything have to be leverage in every situation? I live and work in the Seattle area and may not get paid the same amount as Amazon employees but I certainly get the freedom and encouragement to pursue ways of furthering the company and their future in revenue generating projects. I tend towards the I will give ample notificationt that I will be leaving and will help in making my own job automated eventually. I'd rather leave a trail of automated services than leave another set of people in the lurch because they took a chance on me. One day when I decide to leave there will be enough Go programmers around to maintain what I have built also. Either my services will run until the integrations change their API or I leave knowing that what I have built will maintain itself if I were to take sabbatical and in that case it is no longer my responsibility. The argument that a single developer is worse than a group of developer is old hat when it's clear that an entire team of developers can up and quit and be a single point of failure either in an individual company with a set of nerds or their outsourced company where all developers decide to unionize or the brain of the team leaves and the remainder of the people may be able to sustain the service or don't have the capacity to. Third party services are just as susceptible to these forces but fear should not be a driving factor to hinder the furtherance of your business.