> Full SurrealDB documentation index: https://surrealdb.com/docs/llms.txt

# Working with modules

Scaffold, build, inspect and run Surrealism WebAssembly modules from the command line with surreal db module, and how the mod component of the surreal launcher relates to it.

Modules are WebAssembly extensions that add functions to the database. This page shows the command-line workflow for a [Surrealism](/docs/learn/extensions/plugins/overview.md) module: scaffold a project, build it, inspect the result, and run a function before you deploy it.

`mod` is the launcher's component for this work, and it is the intended home of these commands. Its first release is not published yet, so `surreal install mod` does not work today. Until it is, the same commands are available from the database component as `surreal db module`, and the examples below use that form. The top-level `surreal module` form is deprecated and prints a warning.

## Create a module project

```bash
surreal db module init my-module
```

`init` scaffolds a Rust project with a `surrealism.toml` and a starter `src/lib.rs`. It asks for the organisation and module name interactively. In a script, add `--headless` with `--org`, and `--name` when the module should not take the folder's name.

```bash
surreal db module init my-module --headless --org acme --name my-module
```

## Build the module

Run `build` from the project folder, or name the source folder.

```bash
surreal db module build
surreal db module build ./my-module --out my-module.wasm
```

A build is a release build. Add `--debug` for a debug build.

## Inspect and run it

`info` shows the module's information, and `sig` shows the signature of one of its functions.

```bash
surreal db module info my-module.wasm
surreal db module sig my-module.wasm --fnc greet
```

`run` calls a function with arguments, without a database. Repeat `--arg` for each argument.

```bash
surreal db module run my-module.wasm --fnc greet --arg "World"
```

## Use the module in a database

Define the built file in a database with [`DEFINE MODULE`](/docs/reference/query-language/statements/define/module.md) and call its functions from SurrealQL. The [Surrealism guides](/docs/learn/extensions/plugins/overview.md) cover writing the functions, the attribute reference and deployment.

## Reference

The command reference is [`surreal db module`](/docs/reference/cli/db/commands/module.md) today, and the [modules page](/docs/reference/cli/modules.md) in the CLI reference explains how it relates to `surreal mod`.