The best E2B alternatives in 2026

Open-source sandbox infrastructure with sub-90ms cold starts.

Best for: Teams that want fast code execution sandboxes with an open-source, self-hostable escape hatch.

Daytona is the strongest direct E2B alternative for the classic sandbox job. It pivoted to AI agent infrastructure in early 2025 and now focuses on one thing: spinning up isolated environments for AI-generated code as fast as possible, with cold starts under 90ms. The SDK covers the expected surface (execute code, filesystem access, process management) and the platform is backed by a $24M Series A, so it is not a side project.

Its biggest differentiator against E2B is licensing: Daytona is open source under AGPL-3.0 and self-hostable for free, which matters if you have compliance requirements or want to avoid vendor lock-in on a layer this deep in your stack. What it does not do is host resident agents: like every sandbox on this list, the model is spin up, execute, tear down.

Sandboxes on top of one of the best serverless Python platforms.

Best for: Teams already on Modal, or sandbox workloads that need GPUs attached.

Modal built its reputation on serverless Python with an exceptional developer experience: functions, containers, GPUs, queues and cron that feel instant. Sandboxes are its primitive for running untrusted, AI-generated code with the same per-second billing and the same infrastructure underneath. If your team already runs inference or data pipelines on Modal, adding sandboxed code execution is one import away, and nobody else on this list makes it as easy to attach an H100 to a sandbox.

The honest caveats: sandbox compute is priced at a premium over Modal's base serverless rate (roughly 3x the standard CPU rate), and CPU, memory and GPU are billed as separate line items, so real costs need modeling rather than napkin math. Modal is also a code execution platform, not an agent host: long-lived stateful processes cut against the grain of the serverless model it is built on.

Isolated Linux environments on Cloudflare's network, GA since 2026.

Best for: Teams already building on Cloudflare Workers who want sandboxed execution close to their agent logic.

Cloudflare Sandboxes reached general availability in 2026 as part of the company's push into agent infrastructure, built on Cloudflare Containers. Each sandbox is an isolated Linux environment with a code interpreter, PTY terminal support, secure credential injection and snapshot-based session recovery. The standout pricing decision is active CPU billing: you pay for CPU cycles actually used rather than provisioned time, which is genuinely attractive for agents that sit idle between bursts of work.

The trade-off is ecosystem coupling. Sandboxes require a Workers Paid plan and the true cost spans multiple billing dimensions (Workers requests, Durable Objects, memory, CPU), so the headline vCPU rate is not the whole bill. If your stack is already Workers-first, this is the natural pick; if it is not, you are adopting a platform, not just a sandbox SDK. And while snapshots make sessions recoverable, this is still a sandbox model, not a resident runtime.

Raw microVMs via API, per-second billing, maximum control.

Best for: Infrastructure-strong teams that want to build their own sandbox or agent layer on primitives.

Fly Machines are Firecracker microVMs you create, start, stop and destroy with a single API call, billed per second while running, deployable across Fly's global regions. Stopped machines cost almost nothing. There is no opinionated agent framework on top: you get a fast, hardware-isolated VM and full control over what runs inside it. In early 2026 Fly added Sprites, persistent microVMs with 100GB of NVMe storage and checkpoint/restore in roughly 300ms, aimed squarely at agent workloads that need durable state.

The honest positioning: this is the right layer for teams with real infrastructure engineering capacity who want to own their sandbox or agent orchestration. Everything E2B gives you as an SDK (lifecycle management, code execution APIs, session handling) is yours to build. That is a feature if you have the team for it and a multi-quarter project if you do not.

MicroVM sandboxes that resume in under 25ms with state intact.

Best for: Teams deploying their own agent code who want fast-resuming sandboxes and serverless agent hosting in one place.

Blaxel sits between raw compute and a managed runtime: it is an infrastructure platform built specifically for AI agents, combining microVM sandboxes, serverless agent hosting endpoints and MCP server hosting. Its signature capability is standby: sandboxes suspend indefinitely at essentially zero compute cost (you pay only for snapshot storage) and resume in under 25ms with full filesystem and memory state intact. For agents with intermittent activity, that pricing shape is hard to beat among sandbox vendors.

What Blaxel does not provide is the agent itself. You bring your own runtime and your own logic for keeping an agent coherent over time; Blaxel gives that code fast, well-isolated infrastructure to run on. It is a strong pick for builders who want more agent-awareness than Fly Machines but more control than a fully managed runtime, with the usual caveat that it is a younger platform than most others on this list.

Sandboxes with microVM isolation inside a full developer platform, in their cloud or yours.

Best for: Teams that want sandboxes plus services, jobs and databases on one platform, especially in their own cloud account.

Northflank is a general developer platform (containers, services, cron, databases, CI/CD) that added first-class sandbox capabilities with microVM-grade isolation via Kata Containers and gVisor. Two things make it distinctive as an E2B alternative: some of the lowest published compute rates in the category, billed per second, and self-serve BYOC, meaning sandboxes run inside your own AWS, GCP, Azure or bare-metal account while Northflank provides the control plane. For teams with cloud credits or strict data-residency requirements, that combination is rare.

The flip side of breadth is focus. Northflank is a platform you adopt, not a single-purpose sandbox SDK, and everything agent-specific (session semantics, recovery logic, orchestration) remains yours to design on top of its primitives. It is the right pick when sandboxes are one workload among several you want on unified infrastructure.