I'm streaming data from a desktop application written in C++. It's the step to get it into parquet in the first place.

We use this Rust library to do individual and batch inserts: https://docs.rs/clickhouse/latest/clickhouse/

The error messages for batch inserts are TERRIBLE, but once it’s working it just hums along beautifully.

I’d be surprised if there isn’t a similar library for C++, as I believe clickhouse itself is written in C++

There is an http API and it can eat json and csv too (as well as tons of others)