Frequently asked questions about sim
Short answers. Each links to the page that goes deeper.
- What is sim?
sim (also called sim editor) is the next-generation Vim: a terminal editor written from scratch in Rust that keeps Vim's modal editing and core keys, and shows what is usually hidden: invisible and bidirectional characters, writes from outside the editor, changes against git HEAD, and repositories whose config could run a command. The binary is
sim; the package name issim-editor.- Is sim a fork of Vim?
No. sim is not a fork: it is a new Vim, written from scratch in Rust, that keeps Vim's modal editing and core keys (motions, operators, text objects, counts,
., Visual mode,:sand ranges). It is not fully Vim-compatible: there is no Vim script, no plugins, no config file, and one register so far. Vim registers and macros are planned.- How is sim different from Neovim and Helix?
Neovim and Helix are mature editors with language-server clients, and Neovim is extended with Lua plugins. sim is smaller and trades extensibility for fixed behavior: no plugins, no config files, no modelines, and a visible mark for what is hidden. The comparison page cites a primary source for every claim about the other editors.
- Does sim protect me from everything?
No. sim is not a sandbox: it runs with your privileges. It shows hidden characters, does not run code that files and repositories ask it to run, and does not lose your text. It does not detect look-alike letters from other scripts. Its claims come from the project's own spec and tests, not from an independent audit.
- Does sim read modelines or project configuration?
No. Settings and commands are never read from the contents of a file, and there are no config files or plugins to load from a repository. sim remembers only your choice of look, icons and Markdown view.
- Does sim support language servers?
Not yet. A language-server client whose server runs in a sandbox is planned. sim has syntax highlighting, a file tree, fuzzy file finding and live text search today.
- How do I install sim?
Install with Homebrew. Or build from source. Building from source needs Rust 1.88 or later. Packages for AUR and crates.io are coming soon.
- Which platforms and terminals does sim support?
Linux and macOS, in any terminal. Colors, the kitty keyboard protocol and OSC 52 are used when the terminal offers them (Ghostty, kitty, WezTerm, tmux). Icons need a Nerd Font and can be turned off with
zi.- Is sim fast?
In the project's own benchmark (release build, a 100,000-line file, panel open, highlighting on) a key takes under 1 ms at p99. In a repository of 100,000 files the first frame is drawn in 1.8 to 8.7 ms, measured, against a requirement of 20 ms. The numbers come from the project's spec and one machine (an AMD Ryzen 9 9950X); yours will differ.
- Does sim work with Japanese and other CJK text?
Yes. Wide characters count two columns, prose wraps with Japanese kinsoku rules, word motions split CJK text where the script changes, and with an IME on, full-width keys work as commands.
- Does sim send data anywhere?
sim opens no network connections itself, and the git it starts is configured so that it cannot fetch. This website sets no cookies and loads no third-party scripts or fonts.
- What is the license?
sim is licensed under MIT OR Apache-2.0, at your option. The copyright holder is EFG Technologies.
- Where does the name come from?
sim stands for “Secure vIM”: a Vim built to be secure. Because “sim” alone is ambiguous in search, this site says “sim editor” or “the next-generation Vim” next to it.