Cloudflare Computer vs CubeSandbox: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of Cloudflare Computer and CubeSandbox — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
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Cloudflare Computer
Cloudflare
Cloudflare's virtual filesystem for AI agents — a Durable Object-backed workspace with three pluggable execution runtimes.
Key features
- Durable Object Workspace: The authoritative filesystem state lives in a Durable Object's SQLite store, so agent state is transactional, colocated, and survives worker restarts.
- Pluggable Runtime Backends: One workspace.runtime.exec entry point lets a Workspace register multiple execution backends under stable IDs and pick per call.
- Container Backend: Projects the SQLite state into a sandbox container as a real FUSE mount via computerd — full Linux userland, real binaries, real network.
- Isolate Shell Backend: Runs just-bash inside a Dynamic Worker that reaches the authoritative Workspace over Workers RPC — no container, no second store, no sync round trip.
- Isolate JavaScript Backend: Evaluates ES modules in a fresh Dynamic Worker with structured input/results, durable relative imports, Workspace-backed node:fs/promises, and trusted ws:git and ws:artifacts modules.
- Egress Policy Controls: The examples/egress worker demonstrates matching none, all, or custom egress policies across all three backends for the same request.
- Filesystem-only Mode: A Workspace can be constructed without any backend at all, giving agents just the filesystem surface for tools that don't need execution.
- Worked Examples: The examples/ directory ships runnable Workers — container, worker-shell, worker-javascript, egress, think, and a compare-runtimes UI — each with its own README.
Best for
- Building Coding Agents on Workers: Give a Workers-native agent its own filesystem and shell so it can write code, run tests, and produce artifacts without leaving Cloudflare's edge.
- Comparing Runtimes Side-by-side: The examples/think compare-runtimes UI runs the same task against the container and worker runtimes to profile latency, isolation, and cost.
- Sandboxed User Scripts: Run untrusted user-supplied JavaScript against a per-user Workspace filesystem in an Isolate JavaScript backend with configurable egress.
- Agent Working Directories: A think-style chat agent uses the Workspace as its scratch directory, so files it writes are durable across sessions and reachable by other backends.
- Prototyping Multi-tenant Runtimes: Preview surface for teams designing agent-runtime products on top of Durable Objects, without committing to a single backend design.
- Document Generation Pipelines: The tutorial builds one endpoint whose agent writes a markdown recipe card on the host and runs pandoc in the container to produce a PDF.
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CubeSandbox
TencentCloud
Open-source, hardware-isolated sandbox service for AI agents — sub-60ms cold start, <5MB overhead, E2B-SDK compatible.
Key features
- Sub-60ms Cold Start: Average <60ms boot time and <5MB memory overhead per instance, so a single node can run thousands of agents.
- Hardware-Level Isolation: Each sandbox gets its own Guest OS kernel on RustVMM/KVM — no Docker shared-kernel escape surface for LLM-generated code.
- E2B SDK Compatibility: Drop-in replacement for the E2B SDK — swap one URL env var and existing agent code runs unchanged.
- AutoPause / AutoResume: Idle sandboxes automatically suspend and wake on the next request for aggressive cost optimization.
- Snapshot, Clone & Rollback: CubeCoW copy-on-write engine takes 100ms-granularity checkpoints so agents can fork, roll back, or replay any saved state.
- Credential Vault: Agents call LLMs and external APIs through a proxy — keys never enter the sandbox, model context or logs.
- Egress Control: Per-sandbox domain allowlists with instant block on unauthorized egress and full audit logs for compliance.
- Web Console & Templates: In-browser dashboard at :12088 for managing sandboxes, nodes, version matrix and OCI-image-based templates.
Best for
- Running Untrusted LLM Code: Execute Python/shell that a model wrote without risking the host through hardware isolation.
- E2B Migration: Move existing E2B-based agent workloads to on-prem/self-hosted infrastructure with zero code changes.
- High-Density Agent Fleets: Host thousands of concurrent agent sandboxes on a single node thanks to sub-60ms boot and 5MB overhead.
- Agent Snapshotting: Save state before a risky tool call and roll back on failure using CubeCoW snapshots.
- Compliance-Sensitive Agents: Enforce egress domain allowlists and audit logs for regulated environments.
- Self-Hosted Agent Infra: Deploy a multi-node cluster with the built-in Terraform module for private-cloud AI agent workloads.