nixd

This is inherently a Hard Problem™, since completions may require evaluating arbitrary derivations (e.g. building a custom Linux kernel). For "what symbols are available", the nil LSP implementation[1] works for anything in scope that doesn't require evaluation. It also includes completions for the stdlib and NixOS options (in certain contexts). Another LSP implementation is nixd[2], which is trying to tackle the problem of evaluations for completion. [1] https://github.com/oxalica/nil/ [2] https://github.com/nix-community/nixd

There is this: https://github.com/nix-community/nixd It has jump to definition and autocomplete. Which is very nice. It's not perfect. But it's pretty good