Lifo vs Cloudflare Sandbox: Edge vs Browser
Cloudflare entered the AI sandbox space in 2025 with the Sandbox SDK — container-based code execution running on Cloudflare's global edge network. It's backed by one of the largest infrastructure companies in the world, integrated with Workers AI, and built on a container runtime that gives you a full Linux environment per sandbox.
If you're evaluating a Cloudflare Sandbox alternative, though, there's a question worth asking: does your code actually need to run on an edge server? For a significant category of use cases — AI coding assistants, interactive tutorials, browser-based dev tools — the answer is no. The code can run in the user's browser itself, with zero infrastructure, zero cost, and zero latency.
That's what Lifo does. It's a browser-native operating system — MIT-licensed, fully open-source — that maps Web APIs to POSIX interfaces. No containers, no edge network, no billing. Your code runs in the browser tab.
This post compares both approaches: where Cloudflare Sandbox excels, where Lifo wins, and how to choose.
Architecture: Edge Containers vs Browser Runtime
The fundamental difference is where code executes.
Cloudflare Sandbox runs each sandbox in an isolated container on Cloudflare's edge network. You get a full Linux environment — shell commands, Python, Node.js, file operations, background processes, and exposed HTTP services. The SDK integrates with Workers, so your application code calls sandbox.exec() from a Worker, and execution happens on Cloudflare's infrastructure. Containers are ephemeral by default, though you can mount R2/S3 storage for persistence.
Lifo runs entirely in the user's browser using Web Workers, WebAssembly, and IndexedDB. It provides a bash-like shell, 60+ Unix commands, a persistent virtual filesystem, and a programmatic API. There's no container, no server, no edge node involved. Code executes in the same browser context as your application.
In short: Cloudflare Sandbox is server-side code execution distributed across edge locations. Lifo is client-side code execution with zero server dependency.
Feature Comparison
| Feature | Lifo | Cloudflare Sandbox |
|---|---|---|
| Architecture | Browser (Web Workers + Wasm) | Edge containers (Cloudflare network) |
| Execution location | User's browser | Cloudflare edge (~300 cities) |
| Pricing | Free (MIT license) | Workers Paid plan ($5/mo + usage) |
| Free tier | Unlimited, forever | Workers Free: 100K requests/day |
| Startup time | ~0ms (already in browser) | Container boot (varies) |
| Languages | JS, TS, Python/C/Rust (Wasm) | Python, JS/Node.js, shell, any Linux binary |
| Filesystem | Persistent (IndexedDB) | Ephemeral (R2/S3 mount for persistence) |
| Offline support | Yes | No |
| Shell | Bash-like (60+ commands) | Full Linux shell |
| Isolation | Browser sandbox | Container isolation |
| Network access | Browser fetch API | Full network stack |
| HTTP service exposure | No | Yes (preview URLs) |
| WebSocket support | Limited | Yes (terminal access) |
| Object storage mount | No | Yes (R2, S3, GCS) |
| Open source | Yes (MIT) | SDK open, runtime proprietary |
| Workers AI integration | No | Native |
| Code interpreter | Via Wasm packages | Built-in (Python, JS with rich output) |
| File watching | No | Yes (native fs events) |
| Vendor lock-in | None | Cloudflare ecosystem |
Where Cloudflare Sandbox Wins
Full Linux environment on the edge. Cloudflare Sandbox gives you a real Linux container with real networking, real processes, and real system tools. If your agent needs to run arbitrary shell commands, install system packages, or execute native binaries, Cloudflare delivers a proper server environment — just distributed closer to users than a traditional cloud. This includes running Python with full C extension support (NumPy, pandas, scikit-learn), compiling native code, and launching background processes — none of which are possible in a browser sandbox.
Global edge distribution. Cloudflare's network spans 300+ cities. For latency-sensitive applications where the server-side execution needs to be close to users regardless of their geography, the edge model reduces round-trip times compared to a centralized cloud sandbox (like E2B's single-region setup). If your users are distributed globally and need server-side compute, having execution happen in Singapore for a Singapore-based user — rather than routing to us-east-1 — makes a meaningful difference.
Workers AI integration. If you're already using Cloudflare Workers AI, the Sandbox SDK integrates natively. Your LLM generates code, the sandbox executes it, results flow back — all within the Cloudflare ecosystem. No external API calls, no cross-vendor plumbing. This tight integration means fewer moving parts, simpler debugging, and a single bill for AI inference and code execution.
HTTP service exposure. Cloudflare Sandbox can expose services running inside the container via preview URLs. Build a web app inside the sandbox, and users can access it via a generated URL. This is useful for AI agents that generate full web applications — the user can preview the running app without leaving the conversation. Lifo can't expose services to external clients because it runs inside a browser tab.
Rich code interpreter. The built-in code interpreter supports Python and JavaScript with rich outputs — charts, tables, images. For data analysis use cases (run pandas, generate a matplotlib chart, return the image), Cloudflare's interpreter is more polished out of the box. If your product's core loop is "upload data → AI analyzes it → return visualizations," Cloudflare's interpreter handles this workflow natively.
Object storage mounting. Mount R2, S3, or GCS buckets directly into the sandbox filesystem. For AI agents that need to process files from cloud storage, this is a significant convenience. Your agent can read from and write to cloud storage as if it were a local directory — no custom S3 client code needed.
Where Lifo Wins
Zero cost at any scale. Lifo is MIT-licensed and runs on the user's device. No Workers Paid plan, no per-request charges, no CPU-ms billing. For products where every user interaction triggers code execution — AI assistants, educational platforms, interactive docs — the cost difference compounds. Cloudflare's Workers Paid plan starts at $5/month plus $0.30 per million requests and $0.02 per million CPU-ms. That's affordable for light usage, but at scale it's a line item Lifo eliminates entirely. For a startup with 50,000 daily active users each running 5 sandbox interactions, the difference between $0 and hundreds of dollars per month is the difference between sustainable and unsustainable.
Zero latency per interaction. Even on Cloudflare's edge, every sandbox interaction is a network round-trip. Lifo executes code in the same browser context as your application — sub-millisecond latency on every operation. For AI agent loops with 10-20 tool calls per conversation, this saves 1-4 seconds of cumulative network overhead. In interactive coding assistants where responsiveness determines user satisfaction, this latency advantage is felt on every keystroke and every tool call.
Works offline. Lifo runs without internet. Build products for airplanes, areas with poor connectivity, or privacy-sensitive environments where code can't leave the device. Cloudflare Sandbox requires network access to Cloudflare's infrastructure. For educational products deployed in schools or regions with unreliable connectivity, offline support isn't a nice-to-have — it's a requirement.
Persistent filesystem by default. Lifo's IndexedDB-backed filesystem survives browser refreshes and restarts with zero configuration. Cloudflare Sandbox containers are ephemeral — you need to mount R2 or S3 for persistence, which adds complexity and cost. With Lifo, a user can start a project, close their laptop, and pick up exactly where they left off without any backend infrastructure.
No vendor lock-in. Lifo is MIT-licensed. Fork it, modify it, embed it, compete with its creators — no restrictions. Cloudflare Sandbox ties you to the Cloudflare ecosystem (Workers, R2, Workers AI). If Cloudflare changes pricing, deprecates the SDK, or your business needs to move off their platform, migration is a project. With Lifo, the code is yours. You can inspect every line, patch bugs yourself, and never worry about a vendor decision breaking your product.
No infrastructure to manage. No Workers configuration, no Wrangler deployment, no container images, no R2 bucket setup. Add @lifo-sh/core to your frontend, call Sandbox.create(), and code execution works. The operational simplicity is hard to overstate for small teams. There's no deployment pipeline to maintain, no infrastructure monitoring to set up, and no on-call rotation for sandbox outages — because there's no server to go down.
Cost Comparison
Cloudflare Sandbox (Workers Paid Plan)
| Component | Rate |
|---|---|
| Base subscription | $5/month |
| Requests (first 10M included) | $0.30 per additional million |
| CPU time (first 30M ms included) | $0.02 per additional million CPU-ms |
| R2 storage (if persistence needed) | $0.015/GB/month + operation costs |
Lifo
| Component | Rate |
|---|---|
| Everything | $0 |
Cost at Scale
For an AI coding assistant running 100,000 sandbox sessions/month, each averaging 3 seconds of CPU time:
Cloudflare Sandbox:
- Base: $5/month
- Requests: 100,000 (within included 10M)
- CPU: 100,000 × 3,000ms = 300M CPU-ms → 270M over included 30M → 270 × $0.02 = $5.40
- Total: ~$10.40/month (lightweight usage)
For heavier usage — 1M sessions, 5 seconds CPU each:
- CPU: 1M × 5,000ms = 5B CPU-ms → 4.97B over included → 4,970 × $0.02 = $99.40
- Requests: 1M (within 10M)
- Total: ~$104/month
Lifo: $0 in both scenarios.
Cloudflare's pricing is competitive for cloud execution — cheaper than E2B or Vercel Sandbox at scale. But any number greater than zero is infinitely more than zero.
Real-World Use Cases
AI coding assistant in a SaaS product. Your product lets users describe features in natural language, and an AI agent writes and runs the code. Each conversation triggers 10-15 sandbox interactions. At 100,000 conversations per month, Cloudflare Sandbox costs ~$10-100/month depending on CPU time. Lifo costs $0. If the code being generated is JavaScript or TypeScript (which covers most web development), Lifo handles this entirely client-side with no infrastructure. If the agent needs to run Python data science workflows or install system packages, Cloudflare Sandbox is the better fit.
Interactive documentation site. Your developer docs include runnable code examples — users click "Run" and see output inline. This is a high-volume, low-compute use case. Each interaction is a short code snippet running for milliseconds. Lifo is the clear winner: zero cost, zero latency, works offline, and the sandbox boots instantly when the page loads. Cloudflare Sandbox works but adds unnecessary network overhead and cost for what amounts to running console.log() in a different location.
Multi-agent orchestration platform. You're building a platform where multiple AI agents collaborate — one writes code, another reviews it, a third runs tests. Each agent needs its own isolated environment with full system access. Cloudflare Sandbox's container isolation and full Linux environment make it the right choice here. The agents may need to install packages, run build tools, and expose preview URLs. Lifo's browser sandbox can't match this level of system access.
Educational coding platform. Students learn to code by writing and running exercises in the browser. You need persistent progress (students return to where they left off), offline support (schools have unreliable internet), and zero per-student cost (you can't bill per execution when serving thousands of students on a free tier). Lifo checks every box. Cloudflare Sandbox would work technically but the cost model and internet dependency make it impractical for this use case.
When to Use Which
Use Lifo when:
- Cost is a primary constraint
- You're building client-side tools (browser IDEs, interactive tutorials, AI assistants)
- Offline support matters
- You want zero operational overhead — no Workers config, no deployment pipeline
- Privacy is critical and code must stay on-device
- Your workloads are JS, TS, or Wasm-compilable languages
- You need persistent filesystem out of the box
Use Cloudflare Sandbox when:
- You need server-side execution with full Linux compatibility
- Global edge distribution reduces latency for your use case
- You're already in the Cloudflare ecosystem (Workers, R2, Workers AI)
- Your sandbox needs to expose HTTP services via preview URLs
- You need to mount cloud storage (R2/S3/GCS) into the sandbox
- Rich code interpretation (charts, images) is a core feature
- Your agents need to run native binaries or system-level tools
Use both when:
- Browser-native execution for lightweight, interactive tasks (Lifo) and edge containers for heavy workloads or server-dependent features (Cloudflare Sandbox)
- Free tier for end users (Lifo) with a premium tier backed by edge compute (Cloudflare)
The Bigger Picture
Cloudflare Sandbox represents an interesting third option in the AI sandbox market — not centralized cloud (E2B, Daytona) and not browser-native (Lifo, WebContainers), but edge-distributed containers. The edge model reduces latency compared to centralized cloud, but it's still server-side execution with all the associated costs, network dependencies, and vendor coupling.
Lifo bets that for the majority of AI agent tasks, the browser runtime is sufficient — and that eliminating infrastructure entirely is more valuable than distributing it to more locations. The V8 engine and WebAssembly continue to close the gap with server-side execution every year.
The question for your product isn't "which is better?" but "where does my code actually need to run?" If the answer is "on a server," Cloudflare Sandbox is a strong option. If the answer is "it doesn't matter, as long as it's fast and free," Lifo wins.
Getting Started
Try Lifo — zero setup:
npm install @lifo-sh/core
import { Sandbox } from '@lifo-sh/core';
const sandbox = await Sandbox.create();
const result = await sandbox.exec('echo "No edge node required"');
console.log(result.stdout);
Try Cloudflare Sandbox (requires Workers Paid plan):
import { Sandbox } from '@anthropic-ai/sandbox';
export default {
async fetch(request, env) {
const sandbox = await env.SANDBOX.create();
const result = await sandbox.exec('echo "Running on the edge"');
return new Response(result.stdout);
}
};
Lifo is MIT-licensed and open-source on GitHub.
Frequently Asked Questions
Is Cloudflare Sandbox the same as Cloudflare Workers?
No. Workers are serverless functions that run JavaScript/TypeScript on Cloudflare's edge. The Sandbox SDK is a newer product (currently in beta) that provides isolated Linux containers accessible from Workers. Think of it as: Workers is the compute platform, Sandbox is an isolated execution environment you can call from Workers.
Can Lifo match Cloudflare Sandbox for data analysis tasks?
For basic data analysis with JavaScript libraries, yes. For heavy Python data analysis (pandas, NumPy, matplotlib), Cloudflare Sandbox has an advantage with its built-in code interpreter and full Python runtime. Lifo supports Python via WebAssembly (Pyodide), but native C extensions and plotting libraries have more limited support in the browser compared to a real Linux container.
Is Cloudflare Sandbox cheaper than E2B or Vercel Sandbox?
For lightweight workloads, yes — significantly cheaper. Cloudflare's per-CPU-ms billing means you pay fractions of a cent for short executions. E2B charges $0.05/hr per vCPU (minimum), and Vercel Sandbox charges ~$0.128/core-hour. For sub-second or few-second executions, Cloudflare's model is more cost-efficient. But Lifo is still cheaper than all of them at $0.
Does Cloudflare Sandbox work offline?
No. It requires network access to Cloudflare's edge infrastructure. If your user loses internet connectivity, sandbox execution fails. Lifo is the only AI sandbox option that works fully offline.
Which has better security isolation?
Cloudflare Sandbox uses container-level isolation on their infrastructure — each sandbox runs in its own isolated container. Lifo uses the browser's built-in sandbox (same-origin policy, Web Worker isolation). For running truly untrusted code from external users, container isolation is generally considered stronger. For keeping user data private (code never leaves the device), Lifo's model is inherently more private.