LSP providing
- diagnostics
- code actions
- formatting
Scales well for large files. There is no perceivable delay when editing a 68k line, 5MB file. Diagnostics, code actions, and formatting take less than 20ms

quick start
Configure your lsp client of choice to run jjp lsp
For example, here's a Helix configuration
# languages.toml
[]
= "jjp"
= ["lsp"]
[[]]
= "json"
= ["jjp"]