Top CoreWeave Sandbox alternatives for AI agent workloads in 2026

The right platform depends on where your team starts and what your workloads require. The following dimensions determine whether a platform fits production agent infrastructure.

• Isolation model: Kata Containers, Firecracker, and gVisor each offer different trade-offs between boot time and isolation strength. Shared-kernel containers provide weaker guarantees for untrusted code.
• Deployment independence: Some platforms require existing contracted infrastructure to access. Teams that need a standalone solution should evaluate whether a platform is independently accessible.
• BYOC (Bring Your Own Cloud) support: For regulated industries or teams with data residency requirements, sandboxes must run inside the company's own cloud account. Most platforms in this space are managed-only.
• GPU availability: Agents running inference, fine-tuning, or compute-intensive tasks need GPU access on the same platform as sandbox execution.
• Session model: Ephemeral vs persistent, and whether time limits apply. Some platforms impose hard session limits; others support indefinite runtime.
• Platform completeness: Production agent infrastructure typically also requires databases, background workers, APIs, CI/CD, and observability in the same control plane.
• Pricing transparency: Billing models vary significantly. Some charge for provisioned resources; others charge for active usage only. Cost at scale can differ by several multiples between providers.

The platforms below cover the main use cases: production agent deployments, fast SDK integration, long-running coding environments, and stateful agentic workflows.

Northflank provides microVM-backed sandbox infrastructure alongside a full production stack: databases, APIs, workers, CI/CD pipelines, GPU workloads, and observability, all running on Northflank's managed cloud or inside your own VPC.

Sandboxes on Northflank use Kata Containers, Firecracker, or gVisor depending on the workload's isolation requirements, with sandbox creation taking around 1–2 seconds end-to-end. Each isolation model offers different trade-offs between boot time and isolation strength, giving teams the flexibility to match the runtime to their threat model. For a technical comparison, see Kata Containers vs Firecracker vs gVisor.

A key differentiator is self-serve BYOC (Bring Your Own Cloud). Northflank supports deployment into AWS, GCP, Azure, Oracle, CoreWeave, Civo, bare-metal, and on-premises without requiring a sales call. This is particularly relevant for regulated industries and deployments where data residency is a hard requirement. See deploying sandboxes in your cloud for setup details.

Northflank also supports on-demand GPU workloads running alongside sandboxes in the same platform. L4, A100 (40GB and 80GB), H100, H200, and other GPUs are available without quota requests. GPU pricing is all-in: the H100 rate of $2.74/hour covers GPU, CPU, and RAM as a combined rate. See GPUs on Northflank for full hardware details.

• Both ephemeral and persistent sandbox environments with no forced session time limits
• Multi-tenant microVM isolation via Kata Containers, Firecracker, and gVisor
• Self-serve BYOC across AWS, GCP, Azure, Oracle, CoreWeave, Civo, bare-metal, and on-premises
• On-demand GPUs (L4, A100, H100, H200, and more) without quota requests
• Full workload runtime: APIs, workers, databases, CI/CD, and observability in one control plane
• API, CLI, and SSH access
• In production since 2021 across startups, public companies, and government deployments; SOC 2 Type 2 certified

Best for: Teams that need production-grade microVM isolation, no session time limits, self-serve BYOC, GPU workloads alongside sandboxes, or a complete infrastructure stack beyond just sandboxes.

Pricing (PaaS): CPU at $0.01667/vCPU-hour, memory at $0.00833/GB-hour, billed per second. H100 at $2.74/hour (all-in). Full details on the Northflank pricing page.

Modal is a Python-first serverless compute platform. Modal Sandboxes run on gVisor, which intercepts Linux system calls in user space rather than providing a dedicated VM kernel per workload. Sandboxes have no inbound network access by default and are not authorized to access other Modal workspace resources.

The default sandbox timeout is 5 minutes, configurable up to a maximum of 24 hours per session. Longer workflows require filesystem snapshots to preserve state across sessions. Modal has no BYOC option; all workloads run on managed infrastructure.

Modal's sandbox CPU rate is approximately 3x the standard Modal compute rate: $0.00003942/core-second ($0.1419/physical core-hour, equivalent to 2 vCPUs). Regional and non-preemptible multipliers apply on top for production workloads (1.5–1.75x regional, 3x non-preemptible), so the effective rate for non-preemptible US workloads is higher than the listed base price.

• gVisor isolation (user-space kernel interception; not a dedicated VM kernel per workload)
• GPU support across H100, A100, L40S, L4, A10, T4
• Python SDK; JavaScript and Go SDKs are available but in earlier stages
• Default 5-minute session timeout, configurable up to 24 hours
• No BYOC; managed infrastructure only
• Persistent storage via Volumes at $0.09/GiB-month (1 TiB/month included free)

Best for: Python-first ML teams running inference, training, or RL pipelines who need GPU access alongside sandboxing in one managed platform.

Pricing: CPU at $0.1419/physical core-hour (2 vCPU equivalent), memory at $0.0242/GiB-hour, billed per second. GPU at standard Modal rates (H100: $3.95/hr, A100 40GB: $2.10/hr). Regional and non-preemptible multipliers apply.

For comparisons, see E2B vs Modal and top Modal Sandboxes alternatives.

E2B provides sandbox infrastructure for AI agents with Python and TypeScript SDKs and Firecracker microVM isolation. Each sandbox runs in an isolated Linux VM with a dedicated kernel. The SDK supports integration with LangChain, OpenAI, and Anthropic tooling.

Session limits apply: up to 1 hour on the Hobby plan and up to 24 hours on Pro. E2B does not provide GPU compute. BYOC is available for enterprise customers only and requires contact with sales.

• Firecracker microVM isolation with a dedicated kernel per sandbox
• Python, JavaScript, and TypeScript SDKs with AI framework integrations
• Default 2 vCPU / 512 MiB RAM, configurable up to 8 vCPU / 8 GiB on Pro
• Session limit: 1 hour on Hobby, 24 hours on Pro
• No GPU support
• BYOC: enterprise only, not self-serve; AWS and GCP only

Best for: Teams building coding agents or code interpreter experiences that need Python and TypeScript SDK integrations and sessions within the plan time limits.

Pricing: CPU billed per second: 2 vCPU at $0.000028/second ($0.1008/hour). Memory at $0.0000045/GiB-second ($0.0162/GiB-hour). Storage included free within plan limits.

For a comparison, see E2B vs Modal and self-hostable alternatives to E2B.

Fly.io Sprites provides stateful sandbox environments for AI coding agents. Each Sprite is a persistent Linux environment running on a Firecracker VM. The filesystem is backed by tiered storage: an active NVMe layer for local working data and durable object storage underneath, so the same data is present on every run regardless of whether the Sprite was inactive.

Sprites do not provide GPU support or BYOC. All environments run on Fly.io's managed infrastructure.

• Firecracker VM isolation with a dedicated kernel per Sprite
• Persistent tiered storage: NVMe active layer backed by durable object storage
• Checkpoint and restore in approximately 300ms
• Up to 8 CPUs and 16GB RAM per Sprite
• CLI, REST API, JavaScript, and Go clients
• No GPU support; no BYOC

Best for: Teams building coding agents that need persistent, stateful environments with idle-based billing and checkpoint/restore for long-running or intermittent agent sessions.

Pricing: CPU at $0.07/CPU-hour (cgroup actual usage), memory at $0.04375/GB-hour, hot NVMe storage at $0.000683/GB-hour, durable storage at $0.000027/GB-hour.

Runloop provides microVM-isolated Devboxes for AI coding agents. Devboxes provide hardware-level isolation between tenants. The platform includes integrated benchmark support: teams can run their agents against SWE-Bench Verified, SWE-smith, and other public benchmarks directly from the platform on the Basic plan, with custom benchmarks available on Pro.

Devboxes support suspend and resume: compute billing stops on suspension, and storage billing continues. Snapshot and branch from Devbox disk state is available on Pro. Blueprints allow pre-built templates with custom configuration, and Repo Connections infer build environments from Git repositories automatically.

Runloop supports deployment to a customer VPC on the Enterprise plan. No GPU support is available.

• MicroVM-level hardware isolation between tenants
• Suspend and resume: compute billing stops on suspension
• Blueprints for pre-built, shareable Devbox templates
• Repo Connections for automatic build environment inference from Git
• VPC deployment on Enterprise
• No GPU support

Best for: Teams building AI coding agents that need stateful Devboxes with suspend/resume, snapshot branching, and integrated evaluation benchmarks for agentic workflows.

Pricing: CPU at $0.108/CPU-hour, memory at $0.0252/GB-hour, Devbox storage at $0.00034236/GB-hour, all billed per second.

Pricing as of May 2026. Verify current rates on each platform's pricing page before making cost decisions.

Not all sandbox platforms can run inside your own cloud account. BYOC support determines whether a team with data residency requirements or an existing cloud contract can use a platform at all. The table below shows which platforms support BYOC, what clouds they cover, and how access is granted.

Northflank is the only platform in this comparison with self-serve BYOC and publicly available pricing for that model. For a detailed cost breakdown across deployment models, see the AI sandbox pricing guide and top BYOC AI sandboxes.

The right choice depends on your team's starting point, infrastructure requirements, and the type of workloads your agents run.

Teams not already on CoreWeave infrastructure who need a standalone production sandbox platform with self-serve BYOC, GPU access, and multi-tenant microVM isolation across clouds will find Northflank the most complete option in this comparison. For related reading, see best enterprise AI sandbox platforms, GPU sandboxes, and reinforcement learning agents in secure sandboxes.

CoreWeave Sandboxes is an execution layer for reinforcement learning, agent tool use, and model evaluation, built for teams running workloads on CoreWeave infrastructure. It supports two modes: an on-cluster mode via CKS, which runs sandboxes inside the team's existing cluster, and a serverless mode via Weights & Biases that uses Kata VM isolation. It launched in public preview in May 2026.

The CKS mode requires an existing CoreWeave Kubernetes Service cluster. The serverless mode is accessible through a Weights & Biases account without a CKS cluster. Teams without a CoreWeave infrastructure relationship who need standalone sandbox infrastructure should evaluate the alternatives in this article.

Northflank and Modal both support GPU workloads alongside sandboxes. Northflank supports L4, A100 (40GB and 80GB), H100, H200, and others with all-in pricing and self-serve access, including on BYOC clusters. Modal supports H100, A100, L40S, L4, A10, and T4 with per-second billing. E2B, Fly.io Sprites, and Runloop do not provide GPU compute. CoreWeave Sandboxes supports GPU scheduling on CKS clusters using the same GPU node types used for training.

Northflank is the only platform in this comparison with self-serve BYOC and publicly available pricing. Deployment into AWS, GCP, Azure, Oracle, CoreWeave, Civo, bare-metal, and on-premises is available without a sales call. E2B and Runloop offer BYOC on enterprise plans that require contacting sales. Modal and Fly.io Sprites are managed-only. For more detail, see best BYOC sandbox platforms.

CoreWeave Sandboxes is built for teams already running training workloads on CoreWeave, providing an execution layer co-located with that infrastructure. Northflank is a standalone platform that can run inside CoreWeave via BYOC alongside AWS, GCP, Azure, and other clouds. Northflank covers a broader set of use cases: multi-tenant sandboxes for untrusted code execution, persistent and ephemeral environments, GPU workloads, databases, workers, CI/CD, and observability in one control plane. For setup details, see CoreWeave on Northflank.

On PaaS, Northflank has the lowest published CPU rate at $0.01667/vCPU-hour among the platforms in this comparison with transparent pricing. On BYOC, Northflank is the only platform with self-serve access and publicly available pricing. See the AI sandbox pricing guide for a full cost breakdown across providers and workload specifications.