It really depends on the use case.
- If it is IO intensive, I'd go with something reactive, e.g. ExpressJs on Node, SpringWebFlux or may be even Vertx
- If it is compute intensive, go with something made to handle CPU intensive tasks, you can consider Spring or Python, Go etc
Sometimes it also depends on how fast you can get it up and running. Those times I'd always go with something the team is familiar with and what is easy to setup ( for me its usually Nodejs )