Ask HN: A company is going to profit from my code unfairly
My clients where using an internal monolitic aplication for invoicing, warehouse, etc. Great part of my job was coding a connector between their internal app and {{bigname_saas}}. My app handled updating products from their internal aplication, real time stock sync, mass discounts and some other features.
Now, they want to stop using my services. They want me replaced by the developers of their internal app. This developers have many clients in the same sector.
One of my selling points to gain my client in first place was 0 lockdown. If they wanted to move on it would be easy, because they were using {{bigname.saas}} and not some propietary solution.
Now I feel moraly and legally obligated to handle my code to the developers. And I fear this developers will use my code to other clients, because it's in fact a complete integration with {{bigname_saas}}.
I think is just unfair. I coded the connector for my client to use, and not for this other developers.
Could I use some "exclusive license"? Even if possible I don't think I could enforce it.
I have to handle over my functions this month, my licensing knowledge is almost none.
I think my best option is handle it, learn the lesson, and call it a day.
Any advice?