Harper: grammar checking without sending text away

I wanted grammar checking for my notes, but not enough to send every draft to a large online service. Harper is an interesting alternative: it is open source, written in Rust, and designed to run locally. That makes its privacy story pleasantly simple—the text can stay on my machine.

For writing, the most useful entry point is harper-ls, Harper’s language server. An editor can use it to underline possible mistakes and offer fixes in the same way it reports programming-language diagnostics. It understands Markdown, so it fits a static blog without requiring anything in the generated site or on the web server.

Harper is also a good Rust experiment. Its core is available as a library and can run through WebAssembly, which leaves room for a future browser demo. For now, though, using the language server while editing gives me the useful part without adding another service to maintain.