Configure Core not to download blocks or relay tx automatically

[readyrocky]

More basically: how can I broadcast a tx without having to bear with the burden of a full node and without relying to public APIs?

Can this be achieved with Core and some confs like -prune:<N> ?

[unholycactus]

You can't use Bitcoin Core properly if it isn't synced i.e. you've downloaded all the blocks at least once.
Pruning can be used but you still need to be downloading the new blocks, less space is required if that's what you're looking for.

[achow101]

You cannot have Core function properly without downloading all of the blocks. You can enable pruning so that it does not take up as much space, but it will still need to download and verify all of the blocks before discarding them. This will still take up a lot of bandwidth though.

You can run Bitcoin Core in blocksonly mode (with the -blocksonly option) where it will not download, verify, or relay any unconfirmed transactions. It will still need to download confirmed transactions as those are part of blocks.

[gmaxwell]

https://github.com/laanwj/bitcoin-submittx

[readyrocky]

https://github.com/laanwj/bitcoin-submittx

Thanks a lot!