Extensions

What is an extension?

An extension is a self-contained package that overlays a template/ tree (and optional metadata) onto a scaffolded V project. Extensions are composable: you can apply multiple compatible extensions in a single command and they are merged intelligently.

Each extension may declare which templates it is compatible with (e.g. web-server, cli-app, systems-app), so the CLI only shows relevant options for your chosen starter.

create-vlang-app my-app --template web-server --addons v-docker github-setup v-fmt-vet

Extension categories

Extensions are organized into 7 categories covering the most common V project needs.

How extensions work

When the CLI applies an extension it merges the extension's template/ overlay into the scaffolded project:

1. Overlay files — files under the extension's template/ directory are copied onto the project root (same pattern as CNA/CPA).
2. v.mod / docs — extensions may add Makefile targets, CI workflows, compose files, or docs/ notes without replacing your app entrypoints.
3. Compatibility — optional compatibleWith lists keep database overlays scoped to templates that need them.
4. Incompatibilities — conflicting combinations are rejected when declared by the bank metadata.

Extension file structure

Extensions live in the extensions/ directory of the cva-templates repository:

extensions/
└── your-extension-name/
    ├── template/         # Files merged into the generated project
    │   ├── .github/      # Optional CI workflows
    │   ├── docs/         # Optional authoring notes
    │   └── ...
    └── README.md

Listing available extensions

create-vlang-app --list-addons

Or browse the full catalogue on the Extensions page, where you can filter by template and category.