What are the best free alternatives to E2B?

AgentBox, OneCLI, Flue, Agent Substrate, DeerFlow. All are reviewed on Stack Gems in the same category (agent orchestration tools); 8 free or open source.

Is there an open-source alternative to E2B?

Yes: AgentBox (OSS/MIT), OneCLI (Apache-2.0), Flue (Apache-2.0), Agent Substrate (Apache-2.0).

Alternatives · Orchestration

E2B alternatives (2026)

E2B: Safe sandboxes for agent-generated code. Hosted convenience.

Its Catch: Hosted by default. You are sending code to E2B infrastructure.

Below: 8 free or free-tier tools from the same category (agent orchestration tools), free and open source first, then the closest match by shared tags. Each keeps its own Catch.

1.AgentBoxTeleport a repo into parallel sandboxed agent VMs
Free / OSS · OSS/MIT · 538 GitHub stars
VerdictMIT parallel agent VM launcher. Reach for it when agents need isolated boxes, not another shared worktree.
CatchVs E2B / Daytona (ephemeral sandboxes) and Coder (durable remote workspaces): AgentBox is the one-command teleport + multi-agent box launcher, not a full workspace control plane. Docker/OrbStack-class virtualization and cloud backend credentials are on you; cloud minutes are not “free forever.”
2.OneCLIApache-2.0 team agent harness — sandboxed personal agents + credential gateway
Free / OSS · Apache-2.0 · 3.6k GitHub stars
VerdictOSS team agent harness with credential injection. Sandbox + gateway for many personal agents; not just another secrets vault.
CatchVs AgentBox / Daytona / E2B: OneCLI is the team harness + credential gateway story, not a generic cloud sandbox product. Vs Infisical: secrets are a means; the product is running agents safely for many people. You still bring model spend and decide which agent CLIs to wire. Cloud convenience is optional — OSS self-host is the forever path.
3.FlueAstro TypeScript harness for autonomous sandbox agents
Free / OSS · Apache-2.0 · 8.5k GitHub stars
VerdictApache-2.0 Astro agent harness. Use when you want programmable TypeScript agents with real sandboxes; bring your own models and host.
CatchVs AgentBox and Octop: Flue is a TypeScript framework for authoring agent harnesses, not a multi-user agent platform or a generic sandbox/VM launcher. You still bring models, credentials, and operational judgment; a dead flue.dev marketing domain is not required — the GitHub repo is the source of truth.
4.Agent SubstrateHigh-density secure sandbox runtime for idle-heavy agent workloads
Free / OSS · Apache-2.0 · 5.5k GitHub stars
VerdictApache-2.0 agent sandbox runtime. Reach for dense suspend/resume isolation on K8s; bring cluster ops.
CatchVs AgentBox and Flue: Substrate is the dense sandbox/runtime control plane on Kubernetes, not a developer ADE and not a TypeScript harness framework. Ops cost is real — you need cluster competence. README notes it is not an officially supported Google product.
5.DeerFlowMIT long-horizon SuperAgent harness — sandboxes, memory, skills, gateway
Free / OSS · OSS/MIT · 84.1k GitHub stars
VerdictMIT SuperAgent harness when you want sandboxes + skills + gateway in one OSS tree and will bring models plus Docker headroom.
CatchVs OpenHands, LangGraph, and Mastra: DeerFlow is a full SuperAgent product harness with sandboxes/memory/gateway, not an open coding agent alone, a graph orchestration library, or a TypeScript workflow framework. BYO model API keys; Docker sizing is resource-heavy (multi-vCPU/GB guidance); star velocity is extreme (~83k).
6.CubeSandboxApache concurrent lightweight agent sandbox — RustVMM/KVM, E2B-compatible
Free / OSS · Apache-2.0 · 13k GitHub stars
VerdictApache KVM sandbox when you need dense, E2B-shaped isolation on your own Linux hosts; confirm license text and hardware before betting the fleet.
CatchVs E2B, Daytona, and Cloudflare Sandbox: this is a self-hosted RustVMM/KVM sandbox control plane, not a hosted sandbox SaaS, a workspace platform, or an edge isolate runtime. GitHub license detect shows NOASSERTION even though LICENSE is Apache-2.0 — verify the tree before compliance sign-off (a detection caveat). Linux + KVM on x86_64 (ARM64 maturing); ops weight is real.
7.RakazoApache OSS persistent AI teammates — BYO model and sandbox
Free / OSS · Apache-2.0 · 4.6k GitHub stars
VerdictApache self-host teammate stack when you want persistent bots you own with pluggable models/sandboxes; budget Docker and keys, not just the UI.
CatchVs OpenClaw and DeerFlow: Rakazo is a self-host teammate product (web/desktop/mobile + sandboxes), not a multi-channel messaging agent alone or a SuperAgent research harness. Default install is curl|bash of install-images.sh; beta; BYO model + optional paid sandbox providers; Treg has its own license rider if you embed it.
8.AIO SandboxApache one container: browser+shell+files+VS Code+Jupyter+MCP
Free / OSS · Apache-2.0 · 6.2k GitHub stars
VerdictApache self-host all-in-one sandbox when one shared FS with browser+IDE+MCP beats a managed microVM — lock the API key and read the seccomp note before exposing it.
CatchVs E2B, Daytona, and CubeSandbox (Thu managed/microVM sandbox lane): this is a self-host all-in-one container workstation, not hosted Firecracker sandboxes, a managed workspace SaaS, or a KVM density control plane. Quickstart docs use `--security-opt seccomp=unconfined`; set `SANDBOX_API_KEY` or API/Jupyter/VNC stay open by default.

FAQ

What are the best free alternatives to E2B?: AgentBox, OneCLI, Flue, Agent Substrate, DeerFlow. All are reviewed on Stack Gems in the same category (agent orchestration tools); 8 free or open source.
What is the catch with E2B?: Hosted by default. You are sending code to E2B infrastructure.
Is there an open-source alternative to E2B?: Yes: AgentBox (OSS/MIT), OneCLI (Apache-2.0), Flue (Apache-2.0), Agent Substrate (Apache-2.0).

E2B alternatives (2026)

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