--- title: Sandbox SDK description: Build secure, isolated code execution environments powered by Cloudflare Workers and Containers. image: https://developers.cloudflare.com/dev-products-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/sandbox/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Sandbox SDK Build secure, isolated code execution environments Available on Workers Paid plan The Sandbox SDK enables you to run untrusted code securely in isolated environments. Built on [Containers](https://developers.cloudflare.com/containers/), Sandbox SDK provides a simple API for executing commands, managing files, running background processes, and exposing services — all from your [Workers](https://developers.cloudflare.com/workers/) applications. Sandboxes are ideal for building AI agents that need to execute code, interactive development environments, data analysis platforms, CI/CD systems, and any application that needs secure code execution at the edge. Each sandbox runs in its own isolated container with a full Linux environment, providing strong security boundaries while maintaining performance. With Sandbox, you can execute Python scripts, run Node.js applications, analyze data, compile code, and perform complex computations — all with a simple TypeScript API and no infrastructure to manage. * [ Execute Commands ](#tab-panel-10459) * [ Code interpreter ](#tab-panel-10460) * [ File Operations ](#tab-panel-10461) * [ File watching ](#tab-panel-10462) * [ Terminal Access ](#tab-panel-10463) * [ WebSocket connections ](#tab-panel-10464) TypeScript ``` import { getSandbox } from '@cloudflare/sandbox'; export { Sandbox } from '@cloudflare/sandbox'; export default { async fetch(request: Request, env: Env): Promise { const sandbox = getSandbox(env.Sandbox, 'user-123'); // Execute a command and get the result const result = await sandbox.exec('python --version'); return Response.json({ output: result.stdout, exitCode: result.exitCode, success: result.success }); }}; ``` TypeScript ``` import { getSandbox } from '@cloudflare/sandbox'; export { Sandbox } from '@cloudflare/sandbox'; export default { async fetch(request: Request, env: Env): Promise { const sandbox = getSandbox(env.Sandbox, 'user-123'); // Create a Python execution context const ctx = await sandbox.createCodeContext({ language: 'python' }); // Execute Python code with automatic result capture const result = await sandbox.runCode(`import pandas as pddata = {'product': ['A', 'B', 'C'], 'sales': [100, 200, 150]}df = pd.DataFrame(data)df['sales'].sum() # Last expression is automatically returned `, { context: ctx }); return Response.json({ result: result.results?.[0]?.text, logs: result.logs }); } }; ``` TypeScript ``` import { getSandbox } from '@cloudflare/sandbox'; export { Sandbox } from '@cloudflare/sandbox'; export default { async fetch(request: Request, env: Env): Promise { const sandbox = getSandbox(env.Sandbox, 'user-123'); // Create a project structure await sandbox.mkdir('/workspace/project/src', { recursive: true }); // Write files await sandbox.writeFile( '/workspace/project/package.json', JSON.stringify({ name: 'my-app', version: '1.0.0' }) ); // Read a file back const content = await sandbox.readFile('/workspace/project/package.json'); return Response.json({ content }); }}; ``` TypeScript ``` import { getSandbox } from '@cloudflare/sandbox'; export { Sandbox } from '@cloudflare/sandbox'; export default { async fetch(request: Request, env: Env): Promise { const sandbox = getSandbox(env.Sandbox, 'user-123'); // Watch for file changes in real-time const watcher = await sandbox.watch('/workspace/src', { include: ['*.js', '*.ts'], onEvent: (event) => { console.log(`${event.type}: ${event.path}`); if (event.type === 'modify') { // Trigger rebuild or hot reload console.log('Code changed, recompiling...'); } }, onError: (error) => { console.error('Watch error:', error); } }); // Stop watching when done setTimeout(() => watcher.stop(), 60000); return Response.json({ message: 'File watcher started' }); }}; ``` TypeScript ``` import { getSandbox } from '@cloudflare/sandbox'; export { Sandbox } from '@cloudflare/sandbox'; export default { async fetch(request: Request, env: Env): Promise { const url = new URL(request.url); // Terminal WebSocket connection if (url.pathname === '/ws/terminal') { const sandbox = getSandbox(env.Sandbox, 'user-123'); return sandbox.terminal(request, { cols: 80, rows: 24 }); } return Response.json({ message: 'Terminal endpoint' }); }}; ``` Connect browser terminals directly to sandbox shells via WebSocket. Learn more: [Browser terminals](https://developers.cloudflare.com/sandbox/guides/browser-terminals/). TypeScript ``` import { getSandbox } from '@cloudflare/sandbox'; export { Sandbox } from '@cloudflare/sandbox'; export default { async fetch(request: Request, env: Env): Promise { // Connect to WebSocket services in sandbox if (request.headers.get('Upgrade')?.toLowerCase() === 'websocket') { const sandbox = getSandbox(env.Sandbox, 'user-123'); return await sandbox.wsConnect(request, 8080); } return Response.json({ message: 'WebSocket endpoint' }); }}; ``` Connect to WebSocket servers running in sandboxes. Learn more: [WebSocket Connections](https://developers.cloudflare.com/sandbox/guides/websocket-connections/). [ Get started ](https://developers.cloudflare.com/sandbox/get-started/) [ API Reference ](https://developers.cloudflare.com/sandbox/api/) --- ## Features ### Execute commands securely Run shell commands, Python scripts, Node.js applications, and more with streaming output support and automatic timeout handling. [ Learn about command execution ](https://developers.cloudflare.com/sandbox/guides/execute-commands/) ### Manage files and processes Read, write, and manipulate files in the sandbox filesystem. Run background processes, monitor output, and manage long-running operations. [ Learn about file operations ](https://developers.cloudflare.com/sandbox/guides/manage-files/) ### Expose services with preview URLs Expose HTTP services running in your sandbox with automatically generated preview URLs, perfect for interactive development environments and application hosting. [ Learn about preview URLs ](https://developers.cloudflare.com/sandbox/guides/expose-services/) ### Execute code directly Execute Python and JavaScript code with rich outputs including charts, tables, and images. Maintain persistent state between executions for AI-generated code and interactive workflows. [ Learn about code execution ](https://developers.cloudflare.com/sandbox/guides/code-execution/) ### Build interactive terminals Create browser-based terminal interfaces that connect directly to sandbox shells via WebSocket. Build collaborative terminals, interactive development environments, and real-time shell access with automatic reconnection. [ Learn about terminal UIs ](https://developers.cloudflare.com/sandbox/guides/browser-terminals/) ### Persistent storage with object storage Mount S3-compatible object storage (R2, S3, GCS, and more) as local filesystems. Access buckets using standard file operations with data that persists across sandbox lifecycles. Production deployment required. [ Learn about bucket mounting ](https://developers.cloudflare.com/sandbox/guides/mount-buckets/) ### Watch files for real-time changes Monitor files and directories for changes using native filesystem events. Perfect for building hot reloading development servers, build automation systems, and configuration monitoring tools. [ Learn about file watching ](https://developers.cloudflare.com/sandbox/guides/file-watching/) ### Proxy external API requests securely Keep credentials in your Worker while allowing sandboxes to access external APIs. A Worker proxy validates short-lived JWT tokens from the sandbox and injects real credentials at request time. [ Learn about request proxying ](https://developers.cloudflare.com/sandbox/guides/proxy-requests/) --- ## Use Cases Build powerful applications with Sandbox: ### AI Code Execution Execute code generated by Large Language Models safely and reliably. Native integration with [Workers AI](https://developers.cloudflare.com/workers-ai/) models like GPT-OSS enables function calling with sandbox execution. Perfect for AI agents, code assistants, and autonomous systems that need to run untrusted code. ### Data Analysis & Notebooks Create interactive data analysis environments with pandas, NumPy, and Matplotlib. Generate charts, tables, and visualizations with automatic rich output formatting. ### Interactive Development Environments Build cloud IDEs, coding playgrounds, and collaborative development tools with full Linux environments and preview URLs. ### CI/CD & Build Systems Run tests, compile code, and execute build pipelines in isolated environments with parallel execution and streaming logs. --- ## Related products **[Containers](https://developers.cloudflare.com/containers/)** Serverless container runtime that powers Sandbox, enabling you to run any containerized workload on the edge. **[Workers AI](https://developers.cloudflare.com/workers-ai/)** Run machine learning models and LLMs on the network. Combine with Sandbox for secure AI code execution workflows. **[Durable Objects](https://developers.cloudflare.com/durable-objects/)** Stateful coordination layer that enables Sandbox to maintain persistent environments with strong consistency. --- ## More resources [Tutorials](https://developers.cloudflare.com/sandbox/tutorials/) Explore complete examples including AI code execution, data analysis, and interactive environments. [How-to Guides](https://developers.cloudflare.com/sandbox/guides/) Learn how to solve specific problems and implement features with the Sandbox SDK. [API reference](https://developers.cloudflare.com/sandbox/api/) Explore the complete API documentation for the Sandbox SDK. [Concepts](https://developers.cloudflare.com/sandbox/concepts/) Learn about the key concepts and architecture of the Sandbox SDK. [Configuration](https://developers.cloudflare.com/sandbox/configuration/) Learn about the configuration options for the Sandbox SDK. [GitHub Repository](https://github.com/cloudflare/sandbox-sdk) View the SDK source code, report issues, and contribute to the project. [Pricing](https://developers.cloudflare.com/sandbox/platform/pricing/) Understand Sandbox pricing based on the underlying Containers platform. [Limits](https://developers.cloudflare.com/sandbox/platform/limits/) Learn about resource limits, quotas, and best practices for working within them. [Discord Community](https://discord.cloudflare.com) Connect with the community on Discord. 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