Changelog

New updates and improvements at Cloudflare.

Cloudflare Sandbox SDK adds streaming, code interpreter, Git support, process control and more

Aug 05, 2025

We’ve shipped a major release for the @cloudflare/sandbox ↗ SDK, turning it into a full-featured, container-based execution platform that runs securely on Cloudflare Workers.

This update adds live streaming of output, persistent Python and JavaScript code interpreters with rich output support (charts, tables, HTML, JSON), file system access, Git operations, full background process control, and the ability to expose running services via public URLs.

This makes it ideal for building AI agents, CI runners, cloud REPLs, data analysis pipelines, or full developer tools — all without managing infrastructure.

Code interpreter (Python, JS, TS)

Create persistent code contexts with support for rich visual + structured outputs.

createCodeContext(options)

Creates a new code execution context with persistent state.

// Create a Python context
const pythonCtx = await sandbox.createCodeContext({ language: "python" });

// Create a JavaScript context
const jsCtx = await sandbox.createCodeContext({ language: "javascript" });

Options:

language: Programming language ('python' | 'javascript' | 'typescript')
cwd: Working directory (default: /workspace)
envVars: Environment variables for the context

runCode(code, options)

Executes code with optional streaming callbacks.

// Simple execution
const execution = await sandbox.runCode('print("Hello World")', {
  context: pythonCtx,
});

// With streaming callbacks
await sandbox.runCode(
  `
for i in range(5):
    print(f"Step {i}")
    time.sleep(1)
`,
  {
    context: pythonCtx,
    onStdout: (output) => console.log("Real-time:", output.text),
    onResult: (result) => console.log("Result:", result),
  },
);

Options:

language: Programming language ('python' | 'javascript' | 'typescript')
cwd: Working directory (default: /workspace)
envVars: Environment variables for the context

Real-time streaming output

Returns a streaming response for real-time processing.

const stream = await sandbox.runCodeStream(
  "import time; [print(i) for i in range(10)]",
);
// Process the stream as needed

Rich output handling

Interpreter outputs are auto-formatted and returned in multiple formats:

text
html (e.g., Pandas tables)
png, svg (e.g., Matplotlib charts)
json (structured data)
chart (parsed visualizations)

const result = await sandbox.runCode(
  `
import seaborn as sns
import matplotlib.pyplot as plt

data = sns.load_dataset("flights")
pivot = data.pivot("month", "year", "passengers")
sns.heatmap(pivot, annot=True, fmt="d")
plt.title("Flight Passengers")
plt.show()

pivot.to_dict()
`,
  { context: pythonCtx },
);

if (result.png) {
  console.log("Chart output:", result.png);
}

Preview URLs from Exposed Ports

Start background processes and expose them with live URLs.

await sandbox.startProcess("python -m http.server 8000");
const preview = await sandbox.exposePort(8000);

console.log("Live preview at:", preview.url);

Full process lifecycle control

Start, inspect, and terminate long-running background processes.

const process = await sandbox.startProcess("node server.js");
console.log(`Started process ${process.id} with PID ${process.pid}`);

// Monitor the process
const logStream = await sandbox.streamProcessLogs(process.id);
for await (const log of parseSSEStream<LogEvent>(logStream)) {
  console.log(`Server: ${log.data}`);
}

listProcesses() - List all running processes
getProcess(id) - Get detailed process status
killProcess(id, signal) - Terminate specific processes
killAllProcesses() - Kill all processes
streamProcessLogs(id, options) - Stream logs from running processes
getProcessLogs(id) - Get accumulated process output

Git integration

Clone Git repositories directly into the sandbox.

await sandbox.gitCheckout("https://github.com/user/repo", {
  branch: "main",
  targetDir: "my-project",
});

Sandboxes are still experimental. We're using them to explore how isolated, container-like workloads might scale on Cloudflare — and to help define the developer experience around them.

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