Lifo vs E2B: Browser-Native vs Cloud Sandboxes
If you're building AI agents that need to execute code, you've probably come across E2B. It's the most well-known cloud sandbox platform — Firecracker microVMs, sub-200ms startup, pay-per-second billing. For a lot of teams, it's the default choice. But if you're searching for an e2b alternative that doesn't require cloud infrastructure at all, you're not alone.
"Default" doesn't mean "only." E2B is a cloud-first tool. Every sandbox it spins up runs on a remote server. That works fine — until you need something different: zero cost at scale, offline execution, or a sandbox that lives entirely in the user's browser with no infrastructure to manage.
That's where Lifo comes in. Lifo is a browser-native operating system that maps Web APIs to POSIX interfaces. No servers. No containers. No billing. Your code runs in the browser tab itself.
This post compares the two approaches honestly — where each one shines, where each one falls short, and how to pick the right one for your use case.
The Core Architectural Difference
E2B and Lifo solve the same problem — give AI agents a safe place to run code — but they solve it in fundamentally different ways.
E2B: Cloud MicroVMs. Every sandbox is a Firecracker microVM running on E2B's infrastructure (or yours, with BYOC). Your agent makes an API call, E2B spins up an isolated Linux environment, your code runs on the server, and the results come back over the network. You get full Linux compatibility, real filesystem access, and strong isolation. The trade-off: you pay per second, you need an internet connection, and there's always a network round-trip.
Lifo: Browser-Native OS. Lifo runs entirely inside the browser using Web Workers, WebAssembly, and IndexedDB. It maps familiar POSIX interfaces (filesystem, processes, pipes) onto Web APIs. Your code executes in the same browser tab — no network call, no server, no billing meter running. The trade-off: you're constrained to what the browser runtime supports, and you don't get a full Linux kernel.
Neither approach is universally better. They're optimized for different constraints.
Feature-by-Feature Comparison
| Feature | Lifo | E2B |
|---|---|---|
| Execution environment | Browser tab (Web Workers + Wasm) | Firecracker microVM (cloud) |
| Startup time | Instant (already in browser) | ~200ms (microVM boot) |
| Pricing | Free, forever (MIT license) | $0.05/hr per vCPU + $150/mo Pro |
| Offline support | Yes — fully offline capable | No — requires internet |
| Languages | JavaScript, TypeScript, Python (via Wasm), C/Rust (via Wasm) | Any language that runs on Linux |
| Filesystem | IndexedDB-backed virtual FS | Real Linux filesystem |
| Max session | Unlimited (browser tab lifetime) | 1hr (Hobby) / 24hr (Pro) |
| Concurrent sandboxes | Limited by browser tabs/memory | 20 (Hobby) / 100 (Pro) |
| Network access | Browser fetch API | Full network stack |
| Infrastructure required | None | E2B cloud or self-hosted |
| Isolation model | Browser sandbox (same-origin) | Hardware-level (Firecracker) |
| Open source | Yes (MIT) | Yes (Apache 2.0) |
| npm packages | 60+ built-in, growing | Full npm via Linux |
| Self-hostable | N/A (runs client-side) | Yes (BYOC / on-prem) |
Where E2B Wins
E2B is the better choice when you need the full power of a Linux server.
Full language support. E2B runs anything that compiles on Linux — Python with native C extensions, Ruby, Go, Java, Rust binaries, shell scripts. If your agent generates arbitrary code in arbitrary languages, E2B handles it without worrying about Wasm compilation.
Real filesystem and network. Need to download a dataset, install a pip package with C dependencies, or make outbound HTTP requests to third-party APIs from within the sandbox? E2B gives you a real Linux environment with real networking. Lifo's virtual filesystem and browser-constrained networking can't match this.
Hardware-level isolation. Firecracker microVMs provide strong security boundaries — the same technology that powers AWS Lambda. If you're running untrusted code from external users in a multi-tenant environment, E2B's isolation model is battle-tested at scale.
Enterprise features. BYOC deployment, SOC 2 compliance, custom resource allocation (up to 8 vCPUs, 8 GiB RAM per sandbox). E2B is built for production workloads at Fortune 500 companies.
Where Lifo Wins
Lifo is the better choice when you want zero infrastructure, zero cost, or browser-native execution.
Truly zero cost. Lifo is MIT-licensed and runs entirely client-side. There's no usage meter, no per-second billing, no $150/month base fee. For indie developers, startups, or educational platforms that need sandboxed code execution at scale, the cost difference is not marginal — it's the difference between paying thousands per month and paying nothing.
Zero latency. There's no network round-trip. Code executes in the same browser context as your application. For interactive use cases — live coding environments, educational tools, in-browser REPLs — this eliminates the lag that comes with cloud execution.
Offline-first. Lifo works without an internet connection. Build a coding tutorial that works on an airplane. Ship an AI assistant that runs code in the browser without depending on cloud uptime. E2B sandboxes stop working the moment your user loses connectivity.
No infrastructure to manage. No API keys. No server provisioning. No BYOC configuration. No rate limits to worry about. You add Lifo to your frontend, and code execution just works. For developers who don't want to manage cloud infrastructure, this removes an entire category of operational complexity.
Instant startup. E2B advertises sub-200ms microVM boot times, which is fast for cloud. Lifo's startup is effectively zero — the runtime is already loaded in the browser. For applications that spawn hundreds or thousands of sandboxes (like running student code in a classroom), the startup overhead compounds.
Privacy by default. Code never leaves the user's device. There's no server logging your users' code, no data residency questions to answer, no GDPR processor agreements to sign. The sandbox is as private as the browser itself.
Cost Comparison: What You Actually Pay
Let's run the numbers for a realistic scenario: an AI coding assistant that executes 10,000 sandbox sessions per month, averaging 2 minutes each.
E2B (Pro plan, 1 vCPU):
- Base fee: $150/month
- Usage: 10,000 sessions × 120 seconds × $0.000014/s = $16.80/month
- RAM (512 MiB): 10,000 × 120 × $0.0000045 × 0.5 = $2.70/month
- Total: ~$170/month
Lifo:
- Total: $0/month
At 100,000 sessions per month, E2B costs rise to ~$350/month. At 1 million sessions, you're looking at ~$2,100/month. Lifo stays at zero because the compute happens on the end user's device.
The flip side: if your workloads need server-side compute (heavy ML inference, large dataset processing, multi-hour jobs), Lifo can't do that — and E2B's per-second pricing is actually quite efficient for server-class work.
When to Use Which
Use Lifo when:
- You're building client-side tools (in-browser IDEs, educational platforms, interactive docs)
- Your users need to run JavaScript, TypeScript, or Python (via WebAssembly)
- Cost is a primary constraint and you can't afford per-second cloud billing
- Offline support matters (mobile-first apps, unreliable connectivity)
- You want zero operational overhead — no API keys, no servers, no monitoring
- Privacy is critical and code must stay on-device
- You're an indie dev or early-stage startup that needs to ship fast without infrastructure
Use E2B when:
- You need full Linux compatibility (native binaries, C extensions, arbitrary languages)
- Your agent workloads require server-class resources (GPUs, high CPU, lots of RAM)
- You're running untrusted code in a multi-tenant production environment
- Your sandboxes need real network access (API calls, package installs from registries)
- You need enterprise compliance (SOC 2, BYOC, on-prem deployment)
- Session durations are long (hours, not minutes)
Use both when:
- You want browser-native execution for simple, interactive tasks (Lifo) and fall back to cloud sandboxes for heavy workloads (E2B)
- Your product has both a lightweight playground (Lifo) and a production execution layer (E2B)
Real-World Use Cases
Abstract comparisons only go so far. Here's how the Lifo vs E2B decision plays out in real products.
AI Coding Assistants
If you're building a coding assistant that runs inside a web app — think an in-browser copilot that can execute code snippets as part of its workflow — Lifo lets you embed execution directly in the frontend. The user types a prompt, your agent generates code, Lifo runs it in the browser, and the result appears instantly. No API call to a sandbox service, no waiting for a microVM to boot. The entire loop stays client-side.
E2B makes more sense when your assistant needs to execute complex multi-file projects, install system-level dependencies, or run long-running processes. A coding assistant that generates a full Flask app with database migrations needs a real Linux environment — that's E2B's sweet spot.
Educational Platforms
This is where Lifo's zero-cost model becomes transformative. An online coding bootcamp with 10,000 students running exercises simultaneously would face significant cloud costs with E2B. With Lifo, each student's browser is the execution environment. The platform serves static files and Lifo handles the rest. Scaling from 100 to 100,000 students doesn't increase your sandbox costs by a single dollar.
E2B wins for advanced courses that need full Linux environments — system programming, Docker-based workflows, or courses where students need to install arbitrary packages.
Interactive Documentation
Developer docs with runnable code examples are becoming the standard. Lifo is ideal here: embed a sandbox in your docs page, let users modify and run examples in real time, and you never need to provision backend infrastructure. The sandbox loads with the page and works even if the user is on spotty hotel Wi-Fi.
CI/CD and Testing Pipelines
This is firmly E2B territory. Automated test suites need consistent, reproducible server environments with full filesystem access, network capabilities, and the ability to install any dependency. Browser-based execution isn't designed for this.
Browser Extensions and Web Tools
Any product that ships as a browser extension or web-based tool benefits from Lifo's architecture. A browser extension that analyzes code, a web-based data transformation tool, or an in-page AI assistant can all use Lifo to execute code without requiring users to trust a third-party cloud service with their data.
Migration Considerations
If you're currently using E2B and evaluating whether Lifo fits your use case, here are the practical questions to ask:
Can your workloads run in WebAssembly? If your sandboxes primarily execute JavaScript, TypeScript, or Python (pure Python, not packages with native C extensions), Lifo can likely handle them. If you depend on native binaries, system calls, or Linux-specific tooling, stay with E2B.
How critical is network access inside the sandbox? E2B sandboxes can make outbound HTTP requests, install packages from registries, and interact with external services. Lifo's network access is limited to the browser's fetch API. If your sandbox needs to curl an external API or pip install a package at runtime, that's an E2B requirement.
What's your cost sensitivity? If you're a funded startup with predictable sandbox usage, E2B's pricing is reasonable — $0.05/hour per vCPU. If you're an indie developer, an educational nonprofit, or a product where sandbox usage scales with end users (not your own compute), Lifo's free model changes the economics completely.
Do you need to keep code on-device? For privacy-sensitive applications — healthcare, finance, government — keeping user code off third-party servers simplifies compliance. Lifo's browser-native execution means no data processor agreements, no data residency questions, and no server logs containing user code.
The Bigger Picture: Where Sandboxes Are Heading
The AI sandbox space is moving fast. E2B helped define the category with cloud microVMs. But the browser runtime has been quietly catching up — WebAssembly now supports threads, SIMD, and garbage collection. The V8 engine gets faster every release. Browser APIs like the File System Access API and Web GPU are closing gaps that used to require a server.
Lifo bets on this trajectory: that the browser will become a first-class execution environment for most workloads, not just toy demos. E2B bets on the opposite: that server-side isolation will always be necessary for serious work.
Both bets are partially right. The future is probably hybrid — browser-native for the 80% of tasks that don't need a server, cloud sandboxes for the 20% that do.
Getting Started
Try Lifo (zero setup):
# Open lifo.sh in your browser, then:
lifo run node -e "console.log('Hello from the browser')"
# Or install the npm package:
npm install @lifo-sh/core
Try E2B (requires API key):
npm install @e2b/code-interpreter
import { Sandbox } from '@e2b/code-interpreter'
const sandbox = await Sandbox.create()
const execution = await sandbox.runCode('console.log("Hello from the cloud")')
console.log(execution.text)
Both are open source. Both are free to start with. The right choice depends on where your code needs to run — in the browser or on a server.
Frequently Asked Questions
Is Lifo a drop-in replacement for E2B?
No. Lifo and E2B have different architectures and APIs. Lifo runs in the browser; E2B runs on cloud servers. If your current setup depends on E2B's server-side Linux environment, Lifo isn't a direct swap. But if your use case works within browser constraints (JavaScript, TypeScript, Wasm-compiled languages), Lifo can replace E2B entirely — and eliminate your infrastructure costs.
Can I self-host E2B?
Yes. E2B supports BYOC (Bring Your Own Cloud) and on-premise deployment on Enterprise plans. Lifo doesn't need self-hosting because it runs client-side — there's no server to host.
Which one is more secure?
It depends on your threat model. E2B uses Firecracker microVMs with hardware-level isolation — proven technology that also powers AWS Lambda. Lifo uses the browser's built-in sandbox, which isolates code execution via same-origin policy and Web Worker boundaries. For running untrusted third-party code at scale, E2B's isolation is stronger. For keeping user data private (code never leaves the device), Lifo wins.
Does Lifo support Python?
Yes, through WebAssembly. Lifo can run Python via Pyodide and other Wasm-compiled runtimes. However, Python packages that depend on native C extensions (like numpy's BLAS backend) may not be available or may run slower than on a native Linux environment like E2B.
What about latency for AI agent workflows?
E2B adds network latency on every sandbox interaction — typically 50–200ms per round-trip depending on your region and E2B's infrastructure. For agent workflows that involve dozens of tool calls (create file → run code → read output → modify → run again), this latency compounds. Lifo eliminates network latency entirely since execution happens locally. For latency-sensitive agent loops, this can meaningfully improve response times.