Is there an exporter available for BitWarden then? I'm guessing your 1,200 password had a seamless transition because of some tooling the project provides? Is that correct? Cheers.
Not the person you're asking but you can export your passwords to CSV from LastPass and BitWarden can import the CSV. The only issue is that the LastPass export can be a bit sketchy and have a few errors you need to manually fix.
I suppose seamless may have been an oversell. I consider it seamless because BitWarden provides the import functionality for a variety of competitors' exports (XMLs, CSVs, etc), so all I had to do was export my LastPass passwords to my desktop and then import it into BitWarden via the web interface.
HTH
