I currently work for a small (5-10M revenue/yr) e-commerce business. I wrote all the tech infrastructure for our business and sell the same infrastructure as a SaaS product to a few other friends/competitors/business in our field (thru our company, not personally). I am the only technical person at the company - all the code is in my personal github/AWS/API services, etc. There's no contingency plan. If I left, they wouldn't be able to restart the server should anything happen. I make about $100K and spend about 5-10hrs/week fixing bugs.

Nobody has the technical know-how to check my work, or my time estimates. I can say a new feature will take 2 hrs or 2 months and it means nothing to my supervisor. I love the company and my supervisor and all my coworkers.

I've been itching to move on largely because of salary, however I'm wondering if I do in fact change jobs, would it be wise to work out a retainer while they execute on a contingency plan (hiring someone to replace me)? I'm thinking about moving to a different remote job, and with my workload the past two years I could have been working another 40 hr/week job and nobody would have noticed.

How would you go about this situation? If I were older and had a family my current job would be perfect because it gives me so much flexibility, but I feel like I am not learning at all anymore, and I could make much more at a different job. How immoral is it to work two jobs? What kind of retainer could I propose? I think if I had a retainer with them of 10hrs/week I would do exactly the same amount of work I am doing now. How would one come up with a price for that?

Just looking for input on how to navigate this good situation. Thanks!