I think they are all similar. If you pursue efficiency, I still feel that familiarity is efficiency. Whatapp uses Erlang, which is relatively rarely used in China, but it is very efficient and supports more than 400 million users. But their team is familiar with it, but you are not! Again, when pursuing development efficiency, familiarity equals efficiency!

I have seen your question in OSCHINA. Familiar language is the best language

It is recommended to take a look at avoscloud https://cn.avoscloud.com/‎ Just call the cloud on the backend

I think anyone who recommends a good language to you is doing so as someone who has used it or is proficient in it. The same applies to you. The language you are proficient in should be the best for you. Language, every language, can develop and become powerful. Basically, it can be dealt with even if your users do not reach tens of millions or billions of levels.

The familiar is the best

It is recommended to use something you are familiar with. Of course, if you have strong learning ability and problem-solving ability, you can use either python or ruby.
But personally, I prefer to use python, with simple syntax, huge ecological environment, and relatively large room for choice.
The most commonly used framework under Ruby is rails. It seems that it is not suitable for an application like yours. The interaction between the app and the background is mainly data (I have only a brief understanding of ruby, just for reference).
There are more choices under python, such as django (of course the same problem as rails), flask, web.py, tornado, etc.

The level is limited, the above is for reference only

For efficiency golang and nodejs, the most powerful ones are erlang

Look at the project type, high concurrency: java, erlang, etc.;
If it is a relatively innovative app, in order to develop it quickly, use python or ruby; otherwise, a certain news will be released before you have developed it. .

Anyone who suggests you use a certain language has bad intentions.
Use the language you are most comfortable with.

If the purpose of your app is to operate, use Java, the language you are most familiar with

If you have a learning attitude, I recommend using python’s tornado as the backend

Python is not only used for application data analysis, crawlers and system processing on the web. It also has many libraries. Compared with ruby ​​and rails, it is too thin. Some frameworks, tornado, have better performance than django, and it is asynchronous and non-blocking compared to twisted. It’s lightweight and simple, so I recommend python’s tornado

Halo is actually a problem in February. The above is nonsense