Production AI agents executing untrusted code require infrastructure built for security isolation and instant availability. CodeSandbox works for prototyping agent features during early development, but teams hit limits when agents move to production serving real users. Stability issues force migrations when sandboxes need to remain available beyond a few days without manual recreation.
This guide covers production-grade AI sandbox platforms designed for AI agents that generate and execute untrusted code at scale. We compared each option’s isolation models, resume times from standby, and state persistence capabilities, along with pricing and best use cases.
1. Blaxel
Blaxel provides perpetual sandbox environments where agents execute code with sub-25ms resume times from standby mode. The platform maintains complete filesystem and memory state indefinitely without compute charges during idle periods. This eliminates the cost tension between instant availability and paying for unused infrastructure.
Key features
- Sandboxes resume from standby in under 25ms with exact previous state restored
- Infinite standby duration keeps environments ready without deletion policies that competitors enforce after 30 days
- Micro-VM isolation inspired by the same technology as AWS Lambda provides hardware-enforced tenant boundaries
- Network- and process-based lifecycle transitions sandboxes from active to standby after 1 second of inactivity automatically
- Agent co-hosting deploys agent logic on the same infrastructure as sandboxes to eliminate network roundtrip latency
Pros
- Instant responsiveness enables real-time agent interactions where 300ms delays break user experience
- Zero compute cost during standby combined with 1-second auto-shutdown eliminates idle infrastructure charges
- SOC 2 Type II, HIPAA, and ISO 27001 compliance meets enterprise and industry-specific security requirements
Cons
- CPU-focused infrastructure doesn't support GPU workloads for inference or training
- Cloud-only deployment doesn't serve teams requiring on-premise airgapped installations
Pricing
- Free: Up to $200 in free credits plus usage costs
- Pre-configured sandbox tiers and usage-based pricing: See Blaxel’s pricing page for the most up-to-date pricing information
- Available add-ons: Email support, live Slack support, HIPAA compliance
Who is Blaxel best for?
Blaxel fits teams building production agents requiring instant code execution without infrastructure management overhead. The perpetual standby architecture works particularly well for coding assistants, PR review automation, and data analysis agents where unpredictable timing patterns make traditional always-on or cold-start approaches impractical.
2. E2B
E2B provides open-source sandbox infrastructure based on Firecracker micro-VMs. The platform supports Python and JavaScript execution with full filesystem access, serving teams building data analysis agents, code interpreters, and application generation tools. Self-hosting options allow teams to run E2B infrastructure on their own cloud accounts.
Key features
- Sandboxes boot in approximately 150ms from cold state for quick initialization
- Micro-VM isolation based on Firecracker provides security boundaries at the hypervisor level
- Python and JavaScript SDK support with integration examples for major LLM frameworks
- Code Interpreter SDK handles common agent patterns like data analysis and visualization
Pros
- Open-source infrastructure allows self-hosting for teams requiring full control
- Active community and extensive documentation lower integration friction
- Multi-language sandbox support (Python, JavaScript, TypeScript, Ruby, C++)
Cons
- 30-day deletion policy requires monthly recreation including re-downloading datasets, with no long-term persistence option like volumes
- 10-minute default timeout means paying for full VM runtime unless teams manually manage snapshot lifecycle to pause billing
- Resume from pause takes longer than platforms optimized for instant resume from standby
Pricing
- Hobby (free): One-time $100 of usage in credits, community support, up to 1-hour sessions, and up to 20 concurrent sandboxes
- Pro ($150/month): Up to 24-hour sessions, up to 100 concurrent sandboxes, and customizable compute resources
- Enterprise: Custom pricing for BYOC (Bring Your Own Cloud) and self-hosted deployment options
- Usage-based pricing: See E2B’s pricing page for the most up-to-date pricing information
- Example: 1 vCPU + 2 GB RAM (equivalent to Blaxel XS sandbox, as of February 2026): $0.0828/hour ($0.000014 CPU + 2 × $0.0000045 memory per second)
Who is E2B best for?
E2B suits teams that want open-source infrastructure and self-hosting options when building agent prototypes. Its platform is mostly geared toward development, where 150ms boot times and 30-day recreation cycles align with iterative agent session patterns, rather than production environments with stricter latency demands.
3. Runloop
Runloop provides enterprise devbox infrastructure for AI coding agents with SOC 2–compliant sandboxes that support 10,000+ parallel instances. The platform combines isolated execution environments with snapshot capabilities and benchmark tooling for teams deploying production AI coding assistants.
Key features
- Custom environment images up to 10GB boot in under 2 seconds for complex development environments
- Blueprints standardize environments with pre-installed tools and dependencies across teams
- Snapshots capture complete development state for instant restoration and parallel experimentation
- Micro-VM isolation prevents AI-generated code from escaping sandbox boundaries
- GitHub integration and benchmarking tools validate agent performance against industry standards
Pros
- Enterprise-grade infrastructure with SOC 2 certification meets compliance requirements
- Snapshot and blueprint capabilities accelerate environment setup compared to recreating from scratch
- Massive parallel scaling supports use cases requiring thousands of concurrent agent instances
Cons
- Startup time under 2 seconds works for batch processing but creates latency for real-time interactions
- Focus on AI coding agents means less optimization for general-purpose code execution patterns
- Newer platform compared to established alternatives with shorter production track record
Pricing
- Free: $50 in usage credits for testing
- Pro ($250/month): Suspend/resume with automatic idle detection, repo connections, custom benchmarks
- Enterprise: Custom pricing for VPC deployment and reinforcement fine-tuning (RFT) for feedback-driven improvements
- Usage-based pricing: See Runloop’s pricing page for the most up-to-date pricing information
Who is Runloop best for?
Runloop fits enterprises building specialized AI coding agents for unit testing, code review, or security analysis requiring SOC 2 compliance and dedicated support. Teams needing to scale thousands of parallel agent instances benefit from the platform's benchmarking capabilities and enterprise-grade infrastructure.
Choose execution infrastructure when agents run untrusted code
In this guide we've covered production-grade sandboxing platforms designed for AI agents that generate and execute code at scale. These platforms provide the isolated infrastructure agents need to run untrusted code safely without escaping to host systems.
When your agents need to run untrusted code, consider hardware-isolated sandboxes where generated code runs safely without escaping to host systems or accessing other tenants' data. Look for the following features:
- Resume time from standby (sub-100ms for real-time agents)
- Standby duration limits (30-day caps force you to recreate sandboxes)
- Isolation model (micro-VMs provide stronger boundaries than containers)
Blaxel, a perpetual sandbox platform built specifically for AI agents executing code in production, provides micro-VM isolation (same technology as AWS Lambda) with sub-25ms resume times from standby. Sandboxes automatically return to standby after a few seconds of inactivity, maintaining complete state indefinitely with zero compute charges. And unlike competitors that require minimum billing or automatically delete sandboxes after 30 days, Blaxel's perpetual standby keeps environments ready without idle costs.
Start building with $200 in free credits to test agent code execution with micro-VM isolation, or schedule a demo to discuss your specific agent architecture with Blaxel's founding team.
FAQs about CodeSandbox alternatives
When should you consider alternatives to CodeSandbox?
Consider alternatives when CodeSandbox's 2- to 7-day standby limits force manual sandbox recreation, or when prototype agents move to production serving 1,000+ users daily where infrastructure reliability directly impacts customer experience.
Teams that execute untrusted code need production-grade security isolation (SOC 2, HIPAA) and sub-second resume times that browser-based prototyping environments can't provide.
What migration challenges exist when leaving CodeSandbox?
Migration involves refactoring infrastructure code rather than rewriting agent logic. CodeSandbox projects run in browsers where agents execute code through web interfaces. Production platforms require agent code to interact with sandboxes via REST APIs or SDKs.
Environment variables and secrets need migration from CodeSandbox's configuration to the new platform's secret management. Testing should verify agent-generated code executes correctly in isolated sandboxes and state persists between invocations.
Why does resume time matter for AI agent performance?
Resume time compounds because agents make multiple tool calls per request. A coding assistant might query a database, call a search API, then execute code, where three sequential operations mean three resume penalties.
Platforms with 1- to 3-second cold starts accumulate 3 to 9 seconds of infrastructure delay. E2B's 150ms creates 450ms overhead across three calls. Meanwhile, Blaxel's sub-25ms adds only 75ms total.
Voice agents and coding assistants need sub-100ms total latency for conversational flow. Data analysis agents tolerate higher latency. Match resume requirements to your agent's interaction model.
Why should you use a perpetual sandbox platform?
CodeSandbox's 2- to 7-day standby limits force weekly recreation. E2B extends this to 30 days but still requires monthly rebuilds. Each recreation involves reloading datasets, reinstalling dependencies, and reconfiguring environments, all of which is overhead that compounds when managing multiple agent projects.
Perpetual sandbox platforms like Blaxel eliminate these recreation cycles entirely. Sandboxes hibernate indefinitely with zero compute cost, resuming in under 25 milliseconds with complete state intact. This architecture fits production agents with unpredictable timing patterns, like a PR review agent might process 10 requests one day, then sit idle for two weeks.
