Without more context either party could be in the wrong there.

- The developer for building a non-standard solution that wasn’t asked for and is impossible for the next person to maintain (like those who decide to roll their own database, VCS, encryption, etc)

- or the manager for not understanding the requirements of the build and then expecting developers to redo existing work rather than spending 5 minutes learning the tech stack.

Either way, this is why some orgs refuse to allow any development without a technical design. When you go into a build with a design that everyone agrees on you ensure that expensive development time is focused and less time is wasted rewriting code due to missing requirements.

> expensive development time is focused

Is development time all that expensive? Compared to time spent making different designs.

This is also something I've experienced a lot in large orgs. Having 10 developers +2-3 managers have weeks of endless discussions, design work being done to avoid "costly" development.

Sure developer time is costly, but developers in meetings and design rounds are just as costly if not more so, because more people are involved.

This then gets exacerbated when after weeks of discussion and design an attempt is made to implement an MVP where it is noticed that none of the decisions made work very well for this particular use case.

You can of course face the opposite problem of not designing and implementing something wrong.

This is why I always ask to make a small test first. say you have 5 possible rendering backends for your graphical output, where you don't know which one to use. Spend some developer time building a miniature test to see if the features are there for each one. Often as soon as you start using it you can rule 1 or two out after a few minutes. (Installation breaking). The rest you can sort out in a few hours by modifying the examples they use on their web page.

This often leads to only 1 or 2 actual possibilities, focusing the ensuing design work on what matters.

Who says the developer was building a non-standard solution? I read it as they would use one tool instead of the few that the manager suggested.

Question is, was it use AN api gateway or use THIS api gateway.

It was use THIS api gateway.

Mainly it was exercise in moving from technical work to year long vendor negotiation and setup. The OTHER API gateway blew up despite being used at Netflix. But THIS one is NextGen® so obviously much better.