Upstash Box
Persistent Docker-container "boxes" for coding agents with Claude Code, Codex, OpenCode and Cursor built in, billed on active CPU time rather than wall-clock. A persistent, CPU-time-billed workspace for coding agents that trades VM isolation for cheap idle time.
Overview
Upstash Box, launched on 9 March 2026 by the serverless-data company Upstash, is a "cloud computer for your agents": each box is a Docker container with its own filesystem, process tree and network stack, a shell, git, a chosen runtime (Node, Python, Go, Ruby or Rust on Debian or Alpine) and optionally a built-in coding agent (Claude Code, Codex, OpenCode or Cursor, or a custom agent). You drive it from TypeScript or Python SDKs, a CLI, SSH or the hosted Upstash MCP server, sending prompts or commands and receiving structured results.
Boxes are designed to live indefinitely: they pause when idle, keep their files on durable storage and resume on the next request, and snapshots can branch many boxes from one prepared checkpoint. Pricing is the distinctive part: compute is metered on active CPU time rather than wall-clock, so an idle box costs only storage, with fixed-price keep-alive boxes for always-on use. The trade-off is the isolation boundary, which is a container rather than a VM, something the product page acknowledges when comparing itself with microVM-based providers. Only AWS us-east-1 is available today and no compliance certifications are documented for Box.
Notable
- Launched 9 March 2026 with a free tier
- Billed on active CPU time, not wall-clock: 10% of one core for an hour is quoted at $0.01
- Runs on AWS in us-east-1, with more regions planned
Upstash Box specifications
| Attribute | Details |
|---|---|
| Isolation | Docker container per box with its own filesystem, process tree and network stack; no VM boundary (the product page itself contrasts this with microVM providers) |
| Deployment | Hosted platform |
| Open source | No |
| SDKs and interfaces | JavaScript/TypeScript, Python, CLI, MCP server |
| Cold start (vendor claim) | Not documented |
| Max session length | No maximum stated ("infinite lifespan"); idle boxes auto-pause after 1 hour on the free plan and 6 hours on paid plans, and keep-alive boxes (paid) never pause |
| Persistence | Filesystem (files, packages, git history) persists across pauses and resumes on durable block storage; snapshots capture the filesystem plus agent/runtime settings and can seed many new boxes; memory is not stated to survive a pause |
| GPU | No - not mentioned in the docs or pricing |
| Networking | Outbound allow-all by default (HTTP, HTTPS, DNS, WebSockets, raw TCP); deny-all or a custom allow-list of domains and CIDRs with denied CIDRs can be set at creation or updated live; private IP ranges and cloud metadata endpoints are always blocked; "Attach Headers" inject secret HTTP headers on the host so keys need not enter the box; SSH access by box ID |
| Pricing | Pay as you go per active CPU hour: Small 2 vCPU/4 GB $0.10, Medium 4 vCPU/8 GB $0.20, Large 8 vCPU/16 GB $0.40; memory not billed; storage $0.10/GB-month with 10 GB included per box; keep-alive (always-on) boxes $8, $16 or $32 per box per month. The pricing page is internally inconsistent on Medium/Large vCPU and disk figures |
| Free tier | Free plan: up to 10 concurrent boxes, 5 CPU hours per month, 2 vCPU/4 GB/10 GB boxes, 1-hour idle timeout |
| Compliance | Not documented |
| Regions | AWS us-east-1 only, with more regions planned |
Facts from Upstash Box’s public documentation, verified November 9, 2026. Performance numbers are vendor claims.
Strengths and trade-offs
Strengths
- You want a box an agent returns to for days with files and git history intact
- You need idle time to be free, or a flat monthly price for an always-on box
- You want Claude Code, Codex, OpenCode or Cursor preconfigured rather than installing an agent yourself
- You are already on Upstash and want the same console, API keys and MCP server
Trade-offs
- Container isolation rather than a VM; the vendor itself notes this is a weaker boundary than microVMs
- Single region (AWS us-east-1)
- No compliance certifications documented for Box
- Pricing page figures for Medium and Large sizes are inconsistent between sections
Good fit for: Long-lived per-user coding-agent workspaces where idle time should cost nothing.
Use cases Upstash Box fits
- Coding agents: Per-user coding-agent workspaces that keep filesystem, environment and git state between runs and cost nothing while paused; billed on active CPU.
How Upstash Box compares
| Sandbox | Isolation | Open source | Self-host / BYOC | Cold start (vendor) | Max session | Snapshots / pause | GPU | SDKs |
|---|---|---|---|---|---|---|---|---|
| Upstash Box | Docker container | No | No / No | Not documented | No cap (idle pause 1 h / 6 h) | Yes / Yes | No | JavaScript/TypeScript, Python, CLI, MCP server |
| boat | Full VM, own kernel | No | No / No | Not documented | No cap (auto-stop 1 h default) | Yes / Yes | No | Python, JavaScript/TypeScript, CLI, REST API |
| exe.dev | VM (VMM per VM) | No | No / Yes | ~1 s (claim) | No cap | Yes / Not documented | Not documented | CLI (over SSH), HTTPS API, MCP server |
| Fly.io Sprites | MicroVM | No | No / No | 0.1–2 s wake | Unlimited | Yes / Yes | No | JavaScript/TypeScript, Go, Python, Elixir |
| Daytona | Containers or VMs | No | Not documented / Yes | <90 ms | Unlimited | Yes / Yes | Yes | Python, TypeScript, Ruby, Go, Java |
| Railway Sandboxes | Linux VM | No | No / No | Not documented | No cap (idle 30 min default) | Yes / No | Not documented | JavaScript/TypeScript, CLI, GraphQL API |
| Freestyle | VM | No | No / Not documented | 65 ms | Unlimited (paid) | Yes / Yes | Not documented | TypeScript |
Frequently asked questions
What is Upstash Box?
How does Upstash Box isolate code?
Is Upstash Box open source?
How much does Upstash Box cost?
What are the alternatives to Upstash Box?
Sources
Cite this page
Agent Sandboxes. (2026). Upstash Box. agentsandboxes.org. Last reviewed November 9, 2026. https://agentsandboxes.org/sandboxes/upstash-box/
Found an error or a missing sandbox? Submit a correction — every entry links to the sources it relies on.