OXP Host for VS Code

One extension bundle. Every editor.

Write your extension once as a sandboxed .wasm component and ship it to VS Code, Cursor, Windsurf, VSCodium, and JetBrains IDEs — no recompiling, no forking, no IDE-specific APIs. See oxp.sh.

What is OXP?

OXP (Open Extension Protocol) is an open specification for editor extensions distributed as signed, sandboxed WebAssembly components (WASI Preview 2). The same .oxp bundle runs unchanged in any OXP-compatible host:

This package is the VS Code host: it fetches, verifies, sandboxes, and renders OXP extensions inside VS Code and compatible forks.

Features

• Install from any URL — paste any https://…/extension.oxp (or file://) and the bundle is downloaded, sha256-verified, Ed25519-signature-checked, cached, and loaded into a sandboxed wasm runtime.
• Registry browser — discover extensions at oxp.sh and install with one click via the oxp:// protocol handler.
• Capability-based permissions — every extension declares the capabilities it needs (net.fetch, fs.read, terminal.shell, …) in its manifest. The host shows them in a consent dialog before activation. Cancel = no install. No surprises.
• In-IDE rendering — wasm components draw their UI through the oxp:ui/v1 interface (HTML/CSS in a sandboxed webview, or a declarative component tree). No arbitrary JS injection, no native Electron bypasses.
• Live dev sessions — attach the host to a local oxp dev server and your extension hot-reloads on every save into a dedicated activity-bar view.
• Deterministic bundles — every published .oxp is reproducible (sorted, mtime-stripped tar + zstd) and signed with Ed25519. The digest in the registry matches the bytes you load locally.

Quick start

Install an extension from oxp.sh

The easiest path is the CLI — it handles download, verification, and host registration in one command:

npm install -g @oxprotocol/cli
oxp install @publisher/extension-name

Approve the permission consent prompt and the extension's UI appears as a new panel in VS Code.

You can also install directly from the Command Palette:

1. Open the Command Palette (⇧⌘P / Ctrl+Shift+P).
2. Run OXP: Install Extension from URL… and paste any .oxp URL.
3. Approve the requested capabilities.
4. The extension's UI appears as a new tab.

Install from a local file

# Build your extension
oxp pack
# → dist/myext-0.0.1.oxp

# Install it directly
oxp install-url file:///absolute/path/to/dist/myext-0.0.1.oxp

Or use the Command Palette: OXP: Install Extension from URL… with a file:/// path.

Building your own extension

npm create oxp@latest my-ext       # scaffold a new extension
cd my-ext
npm install
oxp dev                            # hot-reload dev session in VS Code
oxp pack                           # build a signed .oxp bundle
oxp publish                        # ship to https://oxp.sh

Templates available:

The CLI's oxp icon subcommand generates icons from templates, emoji, or SVG:

oxp icon init -t terminal              # built-in template
oxp icon from "🚀"                     # emoji icon (via Twemoji)
oxp icon from "OXP" --bg "#7c3aed"     # monogram
oxp icon convert mylogo.svg --size 256 # rasterise existing SVG

See the full guide at oxp.sh/docs.

Commands

Security

• Sandboxing. Extensions run inside the host-managed wasm runtime with no ambient authority. They cannot read your filesystem, open network sockets, or spawn terminal processes unless they explicitly declare — and you approve — the matching capability.
• Verification. Every bundle's sha256 is computed locally and compared to the value in oxp.json and the registry metadata. Ed25519 signatures are verified against the publisher's public key on every install.
• Allowlists. net.fetch permissions can be scoped to specific hosts (https://api.example.com/*); fs.read to specific paths. Wildcards are rejected for sensitive capabilities.
• No native code. Every OXP extension is a .wasm component. There is no path for an extension to load a native dylib or .node addon.

Report security issues to security@oxp.sh. See SECURITY.md.

Troubleshooting

The activity-bar icon shows a blank square. You may have an older OXP extension installed from a different publisher. List with code --list-extensions --show-versions | grep oxp and uninstall stale entries (code --uninstall-extension oxp.oxp-vscode).

An extension fails to load with WIT_SHA_MISMATCH. The extension was built against a different revision of the oxp:extension world than this host supports. Ask the publisher to rebuild against the current pin (run oxp doctor to see yours).

Permissions dialog never appears. Open OXP: Open Runtime Panel and check that the runtime is running. Permission prompts route through the runtime — if it's not started, installs will queue.

download failed (NOT_WASM). The URL didn't return a valid wasm component. Check the magic bytes — the first four bytes of a valid component are \x00asm.

download failed (SCHEME_NOT_ALLOWED). Plain http:// is only allowed for localhost / 127.0.0.1. Use https:// or file:// for everything else.

Links

• Documentation — https://oxp.sh/docs
• CLI & SDK — https://www.npmjs.com/package/@oxprotocol/cli
• Source — https://github.com/oxprotocol/oxp
• Issues — https://github.com/oxprotocol/oxp/issues

License

Apache-2.0