Recently created a simple nodeJS-mongodb backend for my android app. Is it bad practice to send a potentially big object with arrays to my front end ? I've been struggling implementing this alongside with an ORM because I can't store arrays in my sql ORM.

I guess one would want the ui to be snappy, and waiting for a big object from server might lead to ui not rendering quick enough

You may have a look at www.meteor.com

If it's that big that it really impacts performance you might consider some things;

Do you really need ALL that data?

And can you split it to chunks, so at least the UI will respond quicker while loading the rest lazily.

Can you initialize the download when the user enter the first page, so it's already downloaded once they enter that view?

Can you cache the data at the client and append from that?

And again, do you really need the client to have all that data?

Are you talking in terms of kb or mb?

If the user doesnt have to wait to get their initial load, yiu are good.