I've been using it since 2017 for an Elixir/Phoenix backend, React frontend and PostgreSQL database. It works very well and spares me from having to use three language managers (one for Elixir, one for Erlang and one for JS) plus a docker container for PostgreSQL. I was pleasantly surprised that it manages the database too.
My install of asdf at some point broke so badly, I could not get anything to run. I wish I remembered the exact trouble, but it was bad enough that I just un-installed it in favor of `nvm` for node versioning, and never looked back.
Sibling answers link to the plugin with the details.
The general idea is that it installs the binaries and the data into a subdirectory of ~/.asdf, then sets PATH and the other environment variables to point to there. Then pg_ctl start starts the database.
Each project has its own .tool_versions file so you can have different versions of the same database running in parallel. I was doing that with docker containers but this is easier.
