How do I install Wasmer?

Run `curl https://get.wasmer.io -sSfL | sh`. This installs wasmer CLI and configures your shell to use it. For other platforms, download from https://github.com/wasmerio/wasmer/releases.

What runtime backends does Wasmer support?

Wasmer supports three backends: `singlepass` (fast compilation, low memory, good for JIT), `cranelift` (balanced, default), and `llvm` (maximum performance, AOT compilation). Use `--backend` to switch.

How do I run a wasm file with filesystem access?

Use `wasmer run --dir /path app.wasm`. The `--dir` flag grants the WebAssembly module access to specific directories on your host filesystem. Without it, the module runs in a sandbox with no filesystem access.

What is the difference between wasmer run and wasmer instantiate?

`wasmer run` executes a module and exits. `wasmer instantiate` creates a persistent instance that maintains state across calls, useful when you need to interact with the module multiple times.

How do I compile a wasm module to a native executable?

Use `wasmer create-exe app.wasm --backend llvm`. This compiles the WebAssembly module into a standalone native binary for your platform. The LLVM backend produces the fastest executables.

Wasmer Cheatsheet

Wasmer is a high-performance WebAssembly runtime that lets you run WebAssembly modules safely and quickly on desktops, servers, and embedded environments. This cheatsheet covers Wasmer CLI commands for installation, module execution, WAPM package management, runtime backends, and advanced features.

Updated: 2026-07-20·22 commands

Quick Start

``bash # Install curl https://get.wasmer.io -sSfL | sh

# Check version wasmer --version

# Run a WebAssembly module wasmer run app.wasm

# Validate a module wasmer validate app.wasm

# Inspect module exports wasmer inspect app.wasm`

`Install & Setup`

Command

Description


wasmer --version Check Wasmer version
wasmer self-update Update Wasmer to latest version
wasmer self-uninstall Uninstall Wasmer

Basic Usage
Command Description

wasmer --help Show help information
wasmer validate app.wasm Validate a WebAssembly module
wasmer inspect app.wasm Inspect module imports/exports/metadata
wasmer login Log in to WAPM account
wasmer logout Log out of WAPM account
wasmer whoami Show current logged-in user

Running Modules
Command Description

wasmer run app.wasm Run a WebAssembly module
wasmer run app.wasm --dir /data Run with directory access
wasmer run app.wasm --net Run with network access
wasmer run app.wasm --env KEY=val Run with environment variables
wasmer run app.wasm --backend llvm Run with a specific backend
wasmer run app.wasm --forward-host-env Forward all host env vars

Configuration
Command Description

wasmer config View configuration info
wasmer config --key install_dir Get a specific config value

Package Management
Command Description

wasmer publish Publish a package to WAPM registry
wasmer cache clean Clean Wasmer cache

Advanced
Command Description

wasmer instantiate app.wasm Instantiate and persist module state
wasmer create-exe app.wasm Compile wasm to native executable
wasmer gen app.wasm` Generate language bindings for a module

`Install & Setup(3)`

Command	Level	Example
`wasmer --version` Check Wasmer version	Basic	`wasmer --version`
`wasmer self-update` Update Wasmer to the latest version	Intermediate	`wasmer self-update`
`wasmer self-uninstall` Uninstall Wasmer	Intermediate	`wasmer self-uninstall`

`Basic Usage(6)`

Command	Level	Example
`wasmer --help` Show Wasmer help information	Basic	`wasmer --help`
`wasmer login` Log in to WAPM account	Basic	`wasmer login`
`wasmer logout` Log out of WAPM account	Basic	`wasmer logout`
`wasmer whoami` Show current logged-in user information	Basic	`wasmer whoami`
`wasmer validate` Validate whether a WebAssembly module is valid	Intermediate	`wasmer validate app.wasm`
`wasmer inspect` Inspect imports, exports, and metadata of a WebAssembly module	Intermediate	`wasmer inspect app.wasm`

`Running(6)`

Command	Level	Example
`wasmer run` Run a WebAssembly program	Basic	`wasmer run app.wasm`
`wasmer run --dir` Grant directory access to the WebAssembly program	Intermediate	`wasmer run app.wasm --dir /data`
`wasmer run --net` Enable network access for the WebAssembly program	Intermediate	`wasmer run app.wasm --net`
`wasmer run --env` Set environment variables for the WebAssembly program	Intermediate	`wasmer run app.wasm --env API_KEY=abc123`
`wasmer run --backend` Specify the WebAssembly runtime backend (singlepass/cranelift/llvm)	Expert	`wasmer run app.wasm --backend llvm`
`wasmer run --forward-host-env` Forward all host environment variables to the WebAssembly program	Expert	`wasmer run app.wasm --forward-host-env`

`Configuration(2)`

Command	Level	Example
`wasmer config` View Wasmer configuration info (install path, version, etc.)	Basic	`wasmer config`
`wasmer config --key` Get the value of a specific configuration key	Intermediate	`wasmer config --key install_dir`

`Package Management(2)`

Command	Level	Example
`wasmer publish` Publish a WebAssembly package to the WAPM registry	Intermediate	`wasmer publish`
`wasmer cache clean` Clean the Wasmer cache	Intermediate	`wasmer cache clean`

`Advanced(3)`

Command	Level	Example
`wasmer instantiate` Instantiate a WebAssembly module and persist its state	Expert	`wasmer instantiate app.wasm`
`wasmer create-exe` Compile a WebAssembly module into a native executable	Expert	`wasmer create-exe app.wasm`
`wasmer gen` Generate language bindings for a WebAssembly module	Expert	`wasmer gen app.wasm`

`FAQ`

This cheatsheet is compiled from official tool documentation. Last updated: 2026-07-20.

wasmer --version	Check Wasmer version
wasmer self-update	Update Wasmer to latest version
wasmer self-uninstall	Uninstall Wasmer

wasmer --help	Show help information
wasmer validate app.wasm	Validate a WebAssembly module
wasmer inspect app.wasm	Inspect module imports/exports/metadata
wasmer login	Log in to WAPM account
wasmer logout	Log out of WAPM account
wasmer whoami	Show current logged-in user

wasmer run app.wasm	Run a WebAssembly module
wasmer run app.wasm --dir /data	Run with directory access
wasmer run app.wasm --net	Run with network access
wasmer run app.wasm --env KEY=val	Run with environment variables
wasmer run app.wasm --backend llvm	Run with a specific backend
wasmer run app.wasm --forward-host-env	Forward all host env vars

wasmer config	View configuration info
wasmer config --key install_dir	Get a specific config value

wasmer publish	Publish a package to WAPM registry
wasmer cache clean	Clean Wasmer cache

wasmer instantiate app.wasm	Instantiate and persist module state
wasmer create-exe app.wasm	Compile wasm to native executable
wasmer gen app.wasm`	Generate language bindings for a module