Lightweight sandboxes for your apps and AI agents

Run with the CLI · Embed with the SDK · Try in your browser

Wasmer runs your apps in fast, secure, and lightweight sandboxes: locally, in the cloud, or in your browser.

• Secure by default. You control file, network, and environment access.
• Lightweight. Fast startup with a small memory footprint.
• Ready to run. Python, JavaScript, Bash, and more from the registry.
• Embeddable. Add sandboxes to your app with the Wasmer SDK.

Install the CLI on macOS or Linux:

curl https://get.wasmer.io -sSfL | sh

iwr https://win.wasmer.io -useb | iex

brew install wasmer

Run Python in a sandbox:

wasmer run python/python -- -c "print('Hello from Wasmer')"

Hello from Wasmer

Or try a shell command and Cowsay:

wasmer run wasmer/bash -- -c "echo 'Hello from Wasmer'"
wasmer run syrusakbary/cowsay -- "Hello from Wasmer"

Wasmer downloads the package and caches it for future runs. Use -- to separate Wasmer options from the arguments passed to your program. To work with local files, grant access to a directory with --volume; enable host networking with --net when your program needs it. See the CLI guide for details.

No installation needed: open wasmer.sh to try a sandbox in your browser.

Create a sandbox, choose your tools, and run code directly in your app with the Wasmer SDK.

JavaScript / TypeScript (Node.js 20 or newer):

npm install @wasmer/sdk

[dependencies]
wasmer-sdk = { path = "../wasmer-sdk/rust" }
tokio = { version = "1", features = ["macros", "rt-multi-thread"] }

python -m pip install wasmer-sdk

.package(
    url: "https://github.com/wasmerio/wasmer-sdk.git",
    revision: "wasmer-sdk-swift-v0.2.1"
)

.product(name: "WasmerSDK", package: "wasmer-sdk")

JavaScript / TypeScript

Save this as sandbox.mjs:

import { Wasmer } from "@wasmer/sdk/node";

const wasmer = new Wasmer();
const sandbox = await wasmer.sandboxes.create({
  packages: ["python/python@=3.13.20"],
});

const output = await sandbox
  .command("python", ["-c", "print('Hello from Wasmer')"])
  .run();

console.log(output.text());

Run it with node sandbox.mjs. Python executes inside the sandbox; you don't need Python installed on the host. See the JavaScript guide.

import asyncio

from wasmer_sdk import Wasmer


async def main():
    wasmer = Wasmer()
    sandbox = await wasmer.sandboxes.create(
        packages=["python/python@=3.13.20"],
    )
    output = await sandbox.command(
        "python", ["-c", "print('Hello from Wasmer')"]
    ).run()
    print(output.text())


asyncio.run(main())

import WasmerSDK

let wasmer = try Wasmer()
let sandbox = try await wasmer.sandboxes.create(
    packages: ["python/python@=3.13.20"]
)
let output = try await sandbox
    .command("python", ["-c", "print('Hello from Wasmer')"])
    .run()
print(try output.text())

use wasmer_sdk::{Result, Wasmer};

#[tokio::main]
async fn main() -> Result<()> {
    let wasmer = Wasmer::new()?;
    let sandbox = wasmer
        .sandboxes()
        .create()
        .package("python/python@=3.13.20")
        .await?;

    let output = sandbox
        .command("python")
        .args(["-c", "print('Hello from Wasmer')"])
        .run()
        .await?;

    println!("{}", output.text()?);
    Ok(())
}

Build more with the sandbox API:

• Commands. Run code and capture output.
• Processes. Stream output and manage long-running tasks.
• Files. Read and write the sandbox workspace.
• Tools. Combine languages and packages in one sandbox.
• Services. Run servers with explicit network access.

The SDK is currently alpha. See the language guides for platform support and capabilities, and the SDK examples for Python scripts, an Edge.js HTTP server, PostgreSQL, and multiple tools sharing one sandbox.

Start with packages from the registry:

Explore more packages, package your own software, or deploy an application to Wasmer Edge.

This repository contains the Wasmer runtime and CLI that power the sandbox experience. The sandbox SDKs live in wasmerio/wasmer-sdk. For lower-level WebAssembly embedding, see the Rust API and C API.

• Build Wasmer from source
• Test your changes
• Report a security issue
• Open an issue

Contributions are welcome. For guidance on getting started, read Contributing to Complex Projects. Wasmer is MIT licensed.

Get help, share what you're building, and meet other Wasmer users:

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