When I try to put larger data, the following error is reported:

thread’main’ panicked at’assertion failed: self.len() <= 510’, /root/.cargo/registry/src/mirrors.tools.com-530b4d703ccc752a/sanakirja-core-1.2.16/src/lib.rs:192:9

Is there a way to put longer data at one time without having to cut

Right, it isn’t implemented at the moment, but is completely possible to add. I’ve never needed it myself, since my primary use of Sanakirja is for fixed-sized, short data. What do you want to do with Sanakirja? If you have industrial needs and want that feature, you can contact me at pe@pijul.org.