Prime Sandboxes
Disposable, hardware-isolated microVMs that boot OCI images with Docker inside, built for agentic RL rollouts at the scale of thousands of concurrent sandboxes. A low-cost, RL-oriented microVM sandbox with strong networking and checkpoint features, best for Python-centric teams running rollouts at scale.
Overview
Prime Sandboxes is the sandbox product of Prime Intellect, the decentralised-training company behind the verifiers and prime-rl open-source libraries. Each sandbox is a "hardware-virtualized microVM with its own guest kernel" (the hypervisor is not named) that boots an OCI image as its root filesystem, so Docker, Docker Compose, systemd and kernel-dependent workloads run unmodified. You use the prime_sandboxes Python SDK (sync and async clients, fleets), the prime sandbox CLI or the API; the verifiers library ships SandboxEnv and PythonEnv classes that use them for RL environments.
Sandboxes range from 1 to 16 vCPU, 128 MiB to 64 GiB memory and 2 to 128 GiB disk; the default is 1 vCPU / 1 GiB / 5 GiB with a 60-minute timeout, and lifetimes can be unlimited. Pause/resume preserves memory and processes, filesystem checkpoints can be forked, and outbound networking is governed by domain or CIDR allow/deny rules with secret injection into HTTPS headers. Pricing is purely usage-based ($0.02/vCPU-hour, $0.0125/GiB-hour). New accounts default to 1,024 active sandboxes and 102,400 creations per hour. The product reached general availability on 23 September 2026; GPU sandboxes are "coming soon".
Notable
- General availability announced 23 September 2026; the launch post cites dashboards showing "more than 20,000 concurrent sandboxes".
- Launch pricing ($0.02/vCPU-hour, $0.0125/GiB-hour memory) is stated as valid through 22 December 2026.
- Default account limits: 1,024 active sandboxes, 4,096 vCPUs, 4,096 GiB memory, 32,768 GiB storage.
Prime Sandboxes specifications
| Attribute | Details |
|---|---|
| Isolation | Hardware-virtualised microVM with its own guest kernel per sandbox (hypervisor not named); each boots an OCI/Docker image as its root filesystem and can run Docker, systemd and background services |
| Deployment | Hosted platform |
| Open source | No |
| SDKs and interfaces | Python, CLI, REST API |
| Cold start (vendor claim) | No per-sandbox boot figure; docs say "Thousands can start concurrently in seconds" and the launch post says it can "deploy thousands of sandboxes within seconds" |
| Max session length | Lifetime timeout 1 minute to unlimited (default 60 minutes); idle timeout 1 minute to 1,440 minutes (24 h), disabled by default |
| Persistence | Pause/resume keeps memory and processes intact (paused sandboxes billed for disk only); filesystem checkpoints can be restored or forked and reach a DURABLE state; persistent named volumes can be attached and published; custom images built in the cloud |
| GPU | Listed as "coming soon"; limits table allows 0-8 GPUs but --gpu-count above 0 errors until access is granted |
| Networking | Outbound allow/deny by domain or CIDR, updatable on a running sandbox; header secret injection into HTTPS requests; private sandbox-to-sandbox network at <sandbox-id>.sandbox.internal with per-port rules; public ports and tunnels expose an HTTPS URL |
| Pricing | $0.02 per vCPU-hour, $0.0125 per GiB-hour memory, $0.0002 per GiB-hour disk (launch rates stated as valid through 22 December 2026); example 1 vCPU / 2 GiB / 5 GiB = $0.046/hour; paused sandboxes pay disk only; image and checkpoint storage $0.10 per GiB-month billed hourly, plus a one-day storage charge on upload |
| Free tier | Not documented |
| Compliance | Not documented |
| Regions | Not documented |
Facts from Prime Sandboxes’s public documentation, verified November 9, 2026. Performance numbers are vendor claims.
Strengths and trade-offs
Strengths
- You run large RL or evaluation fleets and want thousands of concurrent microVMs with Docker inside
- You need fine-grained egress rules and header-level secret injection so agents never hold credentials
- You want pause/resume with memory intact and forkable filesystem checkpoints at low hourly rates
- You already use
verifiersorprime-rlfor environments
Trade-offs
- Hypervisor, regions and compliance are not documented
- Only a Python SDK (plus CLI and API); no TypeScript SDK
- GPU sandboxes are not yet available
- No free tier published
Good fit for: RL environment rollouts and agent evaluations that need thousands of Docker-capable microVMs at low hourly cost.
Use cases Prime Sandboxes fits
- RL & evals: Thousands of Docker-capable microVMs at low hourly cost, built for RL environment rollouts and agent evaluations.
How Prime Sandboxes compares
| Sandbox | Isolation | Open source | Self-host / BYOC | Cold start (vendor) | Max session | Snapshots / pause | GPU | SDKs |
|---|---|---|---|---|---|---|---|---|
| Prime Sandboxes | microVM, own kernel | No | No / No | Not documented | 60 min default, unlimited | Yes / Yes | No | Python, CLI, REST API |
| E2B | Firecracker microVM | Yes | Yes / Yes | Not documented | 1 h / 24 h (Pro) | Yes / Yes | No | Python, JavaScript/TypeScript |
| Daytona | Containers or VMs | No | Not documented / Yes | <90 ms | Unlimited | Yes / Yes | Yes | Python, TypeScript, Ruby, Go, Java |
| Modal Sandboxes | gVisor or VM | No | No / Not documented | <1 s | Up to 24 h | Yes / Yes | Yes | Python, JavaScript/TypeScript, Go |
| Lightning AI Sandbox | Not named (isolated Linux env) | No | No / Yes | ms (claimed) | Not documented | Yes / Yes | No | Python, JavaScript/TypeScript, CLI |
| Novita Agent Sandbox | Not documented | No | No / No | <200 ms (claim) | 1 h free / 24 h paid | Yes / Yes | No | Python, JavaScript/TypeScript, CLI |
| Morph Cloud | VM | No | No / Not documented | <250 ms (restore) | Configurable | Yes / Yes | Not documented | Python, TypeScript |
Frequently asked questions
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Sources
Cite this page
Agent Sandboxes. (2026). Prime Sandboxes. agentsandboxes.org. Last reviewed November 9, 2026. https://agentsandboxes.org/sandboxes/prime-intellect-sandboxes/
Found an error or a missing sandbox? Submit a correction — every entry links to the sources it relies on.