JavaScript on the server is in a weird state. While countless frameworks emerge every year, very few manage to gain enough momentum to challenge Express. Even Koa, sometimes billed as Express' successor, has a lower satisfaction ratio (and vastly lower usage numbers).

One interesting entrant in the space is Next.js, which has been generating a lot of interest lately. Although it's not quite comparable to a full-featured Node back-end, its single-minded focus on solving the server-side-rendering problem for React apps has made it a very useful tool.

It's also interesting to see what role serverless technologies like AWS Lambda will play over the next couple of years. Who knows, the back-end category as we know it might soon be a thing of the past!