User Packages Overview

Volt's extension system is a compiled user library. Every plugin is a Rust module under user/, compiled into a shared library that the editor loads at startup:

Platform	Library name
Windows	user.dll
Linux	libuser.so
macOS	libuser.dylib

The Cargo package is named volt-user; the built library artifact is named user.

Architecture

volt (binary)
  → editor-plugin-host   loads packages, wires hooks & commands
  → user/sdk             stable ABI (crate editor-plugin-api)
  → user/ (volt-user)    your compiled plugins
       ├─ lib.rs         package registry & UserLibraryImpl
       ├─ vim.rs, oil.rs, calculator.rs, …
       └─ lang/          per-language packages

• Plugin host (crates/editor-plugin-host) reads PluginPackage metadata and registers commands, keybindings, hooks, and buffers.
• SDK (user/sdk, crate editor-plugin-api) is the only stable ABI boundary. Builtin plugins author against the SDK (plus crates.io), not against internal engine crates.
• The user library builds as both a cdylib (runtime load) and an rlib (dev / in-process API).

User Source Tree (release installs)

Release builds can ship a User Source Tree beside the binary so you can edit builtin plugins and rebuild without the full Volt git checkout:

cd /path/to/install/user
cargo build --release -p volt-user

Inside a running release editor, workspace.compile prefills that build and hot-reloads the new library. See Hot reload.

What lives in the user package

Kind	Examples	Rebuild?
Feature plugins	vim, oil, lsp, git, terminal	Yes (Rust)
Language packages	lang-rust, lang-python, …	Yes
Runtime YAML	config/ui.yaml, config/oil.yaml	Usually no
Themes	themes/*.toml, global.toml	Usually no
Trait wiring	evaluators, autocomplete backends	Yes

Common help questions

You ask	Go here
How do I build the user package?	Build
How do I create a new user plugin?	Create a plugin
I scaffolded a plugin — what next?	After scaffold
How do I edit the vim / oil / compile plugin?	Edit a plugin
What are packages, commands, hooks?	Concepts
Which builtins exist?	Plugin catalog

Related pages

• Getting started
• Configuration
• Troubleshooting