Namespace alternatives
The 6 alternatives below are grouped by kind of sandbox, and each says what it does differently from Namespace. Start from whatever made you look: missing GPUs, session limits, self-hosting, pricing or isolation.
Why teams look beyond Namespace
A CI-grade compute cloud whose VMs and Devboxes suit teams needing macOS or Windows and compliance more than minimal per-sandbox cost.
- Devbox sessions are capped at 3 to 24 hours depending on plan
- Billing has a 1-minute minimum and plan-dependent multipliers, less granular than per-second sandbox pricing
- No cold-start figure, region list or GPU information published
- Two overlapping products (instances and Devboxes) with separate CLIs and billing
Namespace alternatives, by kind
Hosted sandbox platforms
SDK-driven sandboxes you create, run code in and destroy through an API.
Tensorlake Sandboxes
MicroVM sandboxes with memory snapshots, copy-on-the-fly cloning, warm pools and egress policy, alongside hosted Git and a versioned filesystem, with an Apache-2.0 runtime and BYOC on AWS.
- MicroVM (gVisor for GPU)
- Open source
- Self-hostable
- BYOC
- GPU
- Pause/resume
How it differs: Agent harnesses, RL rollouts and coding agents that need memory snapshots, cloning and warm pools at scale. A feature-rich microVM platform for agent harnesses at scale, with open-source and BYOC options that most hosted peers lack.
Compute platforms with sandboxes
General serverless or app platforms that also offer sandboxes, often with GPUs.
Depot Sandboxes
MicroVM sandboxes on the bare-metal compute behind Depot CI, with a TypeScript SDK, Tailscale networking and a Managed Agents service that hosts Claude Code, Codex, Devin and Amp sessions.
- MicroVM on bare metal
- BYOC
- Snapshots
How it differs: Teams on Depot CI who want agent sandboxes and hosted coding-agent sessions billed from the same minute pool. A sensible add-on for Depot CI customers, less compelling as a standalone sandbox given the file-only snapshots and limited SDK coverage.
Railway Sandboxes
On-demand Linux VMs inside a Railway environment with forks, checkpoints, Docker, private networking to your services and per-second billing; generally available since September 2026.
- Linux VM
- Snapshots
How it differs: Coding agents and test runs that need to reach your Railway databases and services over the private network. The natural sandbox for teams already deploying on Railway, strongest when agents need private-network access to existing services.
Cloud development environments
Cloud and in-browser development environments that coding agents increasingly run in.
Coder
Self-hosted cloud development environments defined in Terraform (VMs, Kubernetes pods or Docker containers) for developers and coding agents, with a control-plane-hosted agent loop so workspaces hold no model credentials.
- Template-defined (VM/pod/container)
- Open source
- Self-hostable
- Pause/resume
How it differs: Organisations that want to run coding agents in self-hosted workspaces on their own clusters and clouds with audit and governance. The leading open-source, self-hosted workspace platform for agents and developers, with isolation as strong as the Terraform templates you write.
GitHub Codespaces
GitHub's cloud development environments: a Dev Container running on a freshly built, dedicated VM per codespace, created from the web, `gh` CLI or REST API, billed per core-hour with a free monthly quota.
- Dedicated VM per codespace
- Pause/resume
How it differs: Developer-driven workspaces tied to GitHub repositories, where an agent assists a human inside a Dev Container. A solid VM-isolated workspace for humans and their assistants on GitHub, but its lifecycle and API are not designed for autonomous agent fleets.
Ona (formerly Gitpod)
Enterprise cloud development environments provisioned as isolated VMs (EC2 or Compute Engine) in your own VPC from a Dev Container config, with SDKs, a CLI and Codex-based background agents; hosted Ona Cloud was retired on 31 October 2026.
- Dedicated cloud VM
- BYOC
- GPU
- Pause/resume
How it differs: Enterprises that want VM-isolated, Dev Container-based environments for developers and background agents inside their own AWS or GCP VPC. A mature, VPC-native VM environment platform for enterprises, now enterprise-only and tied to OpenAI's Codex after the Ona Cloud shutdown.
Namespace vs alternatives
| Sandbox | Isolation | Open source | Self-host / BYOC | Cold start (vendor) | Max session | Snapshots / pause | GPU | SDKs |
|---|---|---|---|---|---|---|---|---|
| Namespace | KVM virtual machine | No | No / No | Not documented | Deadline-based; Devbox 3-24 h | Yes / Yes | Not documented | JavaScript/TypeScript, Go, CLI, MCP server, gRPC/Connect API |
| Coder | Template-defined (VM/pod/container) | Yes | Yes / No | Not documented | Not documented | Not documented / Yes | Not documented | CLI, REST API, MCP server |
| Depot Sandboxes | MicroVM on bare metal | No | No / Yes | Not documented | 2 h default timeout | Yes / No | Not documented | JavaScript/TypeScript, CLI |
| GitHub Codespaces | Dedicated VM per codespace | No | No / No | Not documented | 12 h, 30 min idle | No / Yes | No | CLI, REST API |
| Ona (formerly Gitpod) | Dedicated cloud VM | No | No / Yes | Not documented | Not documented | Not documented / Yes | Yes | Python, JavaScript/TypeScript, Go, CLI, REST API |
| Railway Sandboxes | Linux VM | No | No / No | Not documented | No cap (idle 30 min default) | Yes / No | Not documented | JavaScript/TypeScript, CLI, GraphQL API |
| Tensorlake Sandboxes | MicroVM (gVisor for GPU) | Yes | Yes / Yes | ~100s of ms (claim) | 2 h / 24 h / unlimited (Pro) | Yes / Yes | Yes | Python, JavaScript/TypeScript, Rust, CLI, REST API |
Frequently asked questions
What are the main alternatives to Namespace?
Is there an open-source alternative to Namespace?
Cite this page
Agent Sandboxes. (2026). Namespace alternatives. agentsandboxes.org. Last reviewed November 9, 2026. https://agentsandboxes.org/alternatives/namespace/
Found an error or a missing sandbox? Submit a correction — every entry links to the sources it relies on.