E2B vs CodeSandbox vs Blaxel: sandbox comparison 2026

Your coding agent worked in every demo. Then a customer left a session open overnight. When they returned, the sandbox was gone.

Another agent waited over a second for a virtual machine (VM) to wake. Its live preview looked broken. Minor lifecycle decisions during development become production churn.

E2B, CodeSandbox, and Blaxel all run Firecracker microVMs. They differ in lifecycle behavior, networking, and deployment control. This comparison explains where each platform's tradeoffs become important for AI sandboxes running autonomous agents in production.

TLDR

• E2B: Open-source infrastructure with self-hosting on AWS or GCP. Six execution languages. Pro billing adds a monthly base fee. Paused sandboxes require explicit configuration.
• CodeSandbox: Browser-first development environments acquired by Together AI in December 2024. Hibernated snapshots stored on disk for a limited period. Migration toward Together products is underway.
• Blaxel: Infrastructure foundation for autonomous agents. Standby preserves memory and processes indefinitely on higher quota tiers. No base fee. Managed networking includes preview URLs, custom domains, and egress controls.

What is E2B?

E2B sandbox infrastructure runs AI-generated code inside Firecracker microVMs. E2B creates sandboxes from reusable sandbox templates. Existing Dockerfiles convert through the fromDockerfile() method.

Official SDKs cover three supported SDK languages: JavaScript, TypeScript, and Python. E2B runs six execution languages: Python, JavaScript, TypeScript, R, Java, and Bash.

The infrastructure repository uses the Apache 2.0 license. Its Terraform deployment supports Google Cloud Platform (GCP) as stable. Amazon Web Services (AWS) support is beta.

What is CodeSandbox?

CodeSandbox development environments is a cloud development environment platform. Together AI acquired it on December 12, 2024.

Its Firecracker VMs save memory snapshots during hibernation. The TypeScript-based @codesandbox/sdk package includes JavaScript and Python interpreters. It also supports custom Docker images.

CodeSandbox is migrating toward the Together platform. Together AI launched successor products on May 20, 2025. Those products are Together Code Sandbox and Together Code Interpreter.

What is Blaxel?

Blaxel is the infrastructure foundation for autonomous agents. It provides the execution layer where agent-generated code runs in production. Each sandbox uses microVM isolation. After network inactivity, the sandbox enters standby. Standby preserves the filesystem, memory, environment variables, and running processes. For guaranteed long-term persistence, teams attach Volumes.

The platform organizes its products around three primitives. Compute includes Sandboxes and Batch Jobs. Storage combines Agent Drive documentation, in private preview, with Volumes. Networking includes custom domains, domain filtering, and direct preview URLs. It also includes dedicated egress gateways in private preview. Proxy secrets injection is in public preview.

SDKs support Python, TypeScript, and Go. Blaxel is a first-class sandbox provider in the OpenAI Agents SDK. Blaxel Sandboxes handle execution beneath OpenAI's Codex harness. Together, these primitives cover code execution, shared storage, and agent networking.

Head-to-head feature comparison

When Blaxel is the better choice

Blaxel's lifecycle and networking matter most for production agents that remain idle between tasks. These scenarios show where those differences affect users and engineering teams.

• Coding agents with interrupted sessions: Users often leave generated applications open between work periods. Blaxel preserves memory and processes during standby. That behavior reduces lifecycle-related session loss.
• PR review agents: Reviews arrive sporadically, leaving compute idle between pull requests. Blaxel enters standby automatically. It stops compute billing without timer configuration.
• Agents needing production networking: Blaxel manages preview URLs and custom domains. It offers dedicated egress gateways in private preview. Proxy credentials stay outside the sandbox through server-side injection.
• Regulated workloads: Blaxel holds sandbox compliance certifications covering SOC 2 and ISO 27001. A Health Insurance Portability and Accountability Act (HIPAA) Business Associate Agreement (BAA) is available as an add-on.
• Unified infrastructure: Agent Drive is in private preview. It mounts across multiple sandboxes with concurrent read-write access. Sandboxes, Volumes, Batch Jobs, and networking cover related production requirements.

These strengths address persistent production sessions. E2B offers a different advantage through its open-source infrastructure. That model provides more control over deployment and ownership.

When E2B may fit better

E2B's open-source codebase and self-hosting options matter most for teams that need deployment ownership. These scenarios show where E2B's model provides advantages over managed-only platforms.

• Full infrastructure ownership: The e2b-dev/infra repository uses the Apache 2.0 license. Terraform deployments support GCP as stable and AWS as beta. Teams can inspect, fork, or operate the sandbox infrastructure themselves.
• Air-gapped or VPC-isolated deployments: E2B's Bring Your Own Cloud (BYOC) option places sandboxes inside a customer's virtual private cloud (VPC). Sensitive traffic stays off E2B Cloud. Blaxel always manages the control plane, even with Bring Your Own Metal.
• Broader execution-language coverage: E2B executes R and Java alongside Python, JavaScript, TypeScript, and Bash. Blaxel's first-class SDKs cover Python, TypeScript, and Go. Ruby, Java, and Rust hosts use the REST API.
• Fast iterative prototyping: Template-based creation reached approximately 80ms in E2B's documentation. Those creation times support developers rebuilding agent loops throughout the day.
• Lower-commitment evaluation: The Hobby tier fits short development cycles without a base subscription. Pro increases concurrency limits through paid add-ons.

E2B trades automatic standby for deployment control and broader execution-language coverage. Teams should test lifecycle behavior and ownership requirements before choosing.

When CodeSandbox may fit better

CodeSandbox fits teams building development environments primarily for humans. The product served 4.5 million developers monthly when Together AI acquired it. These scenarios show where its model provides advantages.

• Human-first browser development: The January 2025 changelog confirmed CodeSandbox would continue operating normally. HeroUI reduced VM startup from 2 minutes to under 2 seconds on Together Code Sandbox.
• Large VM requirements: VM sizes extend to 64 cores and 128 GB on the XLarge tier. The SDK clones a running VM or snapshot. Together AI claims sub-second cloning.
• Together AI ecosystem alignment: Teams already buying from Together AI get a unified vendor relationship. Together AI launched successor products on May 20, 2025. Those are Together Code Sandbox and Together Code Interpreter.
• Explicit lifecycle control for agents: Agent teams can set hibernationTimeoutSeconds to 86400. They can also call hibernate and resume explicitly. CodeSandbox advises teams not to rely on automatic hibernation behavior.
• SOC 2 compliance at Enterprise tier: CodeSandbox states that its infrastructure and VMs meet SOC 2 Type II requirements. Its pricing page places that compliance feature under Enterprise.

Agent teams should account for migration timelines before committing. CodeSandbox's repository migration guide sets deadlines. New imports stop on April 1, 2026. Full support ends on July 1, 2026. The together-sandbox successor omits several endpoints from public documentation. Those include list, get, hosts, and preview URLs. Long-lived agent sessions require closer attention to archiving and preview support.

Pricing comparison

Pricing changes frequently, so teams should confirm current rates before committing. Use a 2 GB memory configuration as the common baseline. The supplied rates don't document an equivalent CPU configuration across all three vendors. They also don't support matched compute and storage totals. Unavailable cells remain labeled rather than implying direct price parity.

Blaxel pricing follows this format:

• Free: Up to $200 in free credits plus usage costs.
• Pre-configured sandbox tiers and usage-based pricing: See the Blaxel products page for the latest rates.
• Available add-ons: Email support, live Slack support, and HIPAA compliance.

The table retains official E2B and CodeSandbox plan information available in the supplied sources.

Billing behavior matters beyond active-compute rates. E2B kills timed-out sandboxes by default unless teams configure pause behavior. CodeSandbox rounds each run to the next whole minute. Blaxel enters standby after connections close, leaving only snapshot storage costs. For bursty agents, idle behavior can outweigh small active-compute price differences.

Key differentiators and objection handling

Vendor reviews often focus on isolation, vendor viability, and migration cost. Each concern requires a different test rather than a single feature checklist.

"All three run Firecracker. Isn't the isolation identical?"

No. All three platforms use the same broad isolation model. Their security implementations still differ. Firecracker gives each sandbox a separate kernel behind a hardware virtualization boundary. That boundary suits arbitrary, untrusted, or AI-generated code better than shared-kernel containers. However, the hypervisor represents only one security layer. Host configuration, patching, tenancy controls, networking, credential handling, and monitoring still vary by provider.

Firecracker also doesn't filter network traffic itself. Its microVM design documentation assigns egress controls to the host environment. A 2026 security study found that output checks missed 95% of successful prompt-injection attacks. Domain allowlisting blocked all attempted egress during the study's ablation.

E2B provides outbound traffic controls. Allow lists support IP addresses, classless inter-domain routing (CIDR) ranges, and domains. Deny lists support IP addresses and CIDR ranges. Blaxel provides domain filtering and proxy secrets injection in public preview. CodeSandbox doesn't publish equivalent sandbox egress-control documentation. Teams should compare host controls, networking policies, secrets handling, and compliance evidence.

"E2B has the mindshare. Why take vendor risk on a smaller company?"

Portability reduces part of the vendor risk. All three platforms build sandbox environments from Dockerfiles or custom images. Portable images limit environment rebuilding, although lifecycle code remains provider-specific.

The OpenAI Agents release includes hosted clients for several sandbox providers. Version 0.14.0 lists Blaxel, E2B, Daytona, Modal, and others. Teams install providers through extras such as openai-agents[blaxel]. Switching still requires testing, but the shared client surface reduces application changes.

Reported incidents should guide testing rather than prove platform-wide unreliability. An E2B reliability issue describes unreachable sandboxes and synthesized error responses. Another report documents lost retry headers on HTTP 429 responses.

A proof of concept should test unreachable-sandbox handling, retries, concurrency, and state restoration. Vendor evaluation should also cover support, service-level agreements, incident history, and exit planning. Technical portability matters, but production support and documented recovery procedures matter too.

"We're on CodeSandbox already. Migration is the cost."

Migration cost is real, especially when preview URLs and lifecycle calls appear throughout an agent workflow. Existing templates, environment variables, and custom images also require validation. CodeSandbox already documents a repository migration schedule. Teams should compare the cost of following that path against another execution layer. Human development environments may fit GitHub Codespaces or Together's successor products. Stateful coding agents need further testing around hibernation, preview URLs, and archive recovery.

Build0's chief technology officer compared CodeSandbox, Vercel, and Blaxel. He described Blaxel as the most solid platform in the Build0 case study. He also reported 70% to 80% lower costs than previous providers.

Treat that result as one customer's experience, not a universal migration outcome. Start with one existing Dockerfile and one representative agent session. Let the session become idle, then test state restoration and preview behavior. Measure migration effort, resume latency, error handling, and idle charges before moving more traffic.

Run your developer sandbox comparison against real agent traffic

All three vendors use Firecracker microVMs, creating isolation-model parity. The final decision depends on lifecycle controls, networking, deployment ownership, and pricing behavior. E2B offers open-source infrastructure, BYOC, and broad execution-language support. Its plan limits and Pro base fee matter for longer-running production workloads.

CodeSandbox remains strongest as a development environment for human users. Agent teams must account for hibernation, archive behavior, and the ongoing migration toward Together products. Blaxel focuses on coding agents, PR review agents, and data analysis agents. Its standby model reduces lifecycle-related session loss without promising durable storage. Volumes provide long-term persistence when durability is required.

For engineering leaders, this model can align compute spending with active execution. It also consolidates compliance, storage, and networking requirements. Sandboxes and Batch Jobs cover compute. Agent Drive in private preview and Volumes cover storage. Preview URLs, custom domains, egress controls, and secret injection cover networking. Test each platform with the same agent, image, session pattern, and failure cases. Sign up free to test Blaxel, or book a demo for migration planning.

FAQs

Which sandbox platform keeps state longest between agent sessions?

Blaxel keeps standby sandboxes indefinitely on higher quota tiers. The snapshot preserves filesystem, memory, environment variables, and running processes. Standby isn't a durability guarantee, so teams needing permanent retention should attach a Volume. E2B keeps paused sandboxes until the application calls sandbox.kill(), but the default timeout action kills the sandbox. CodeSandbox stores hibernated sandboxes on disk temporarily and deletes inactive workspaces after 8 days. Files requiring guaranteed retention belong on durable storage.

Is E2B cheaper than Blaxel for production agent workloads?

The answer depends on lifecycle behavior, not just active-compute rates. E2B bills per second and stops billing paused sandboxes. Pro adds a monthly base fee for higher concurrency. Blaxel has no base fee and uses usage-based pricing. Standby stops compute charges after network activity ends. That model favors bursty coding and PR review agents. Replay identical traffic against both platforms for a fair comparison. Include active execution, idle periods, concurrency, and support add-ons.

Can I move a Dockerfile-based environment between these platforms?

Yes, but the Dockerfile covers only the environment layer. E2B converts Dockerfiles with fromDockerfile(). CodeSandbox supports custom Docker images based on Debian or Ubuntu. Blaxel also builds sandbox templates from Dockerfiles. Lifecycle, networking, and storage code remain provider-specific. E2B uses pause and resume calls, CodeSandbox uses hibernate behavior, and Blaxel uses automatic standby. The OpenAI Agents SDK provides a shared client interface for E2B and Blaxel. A migration test should cover lifecycle integrations, not only a successful image build.

Which of the three is SOC 2 or HIPAA compliant?

Blaxel compliance information confirms SOC 2 Type II, ISO 27001, and a HIPAA BAA as a paid add-on. E2B publishes a SOC 2 Type II report through its trust center and offers a HIPAA BAA request path. CodeSandbox documents SOC 2 Type II compliance under its Enterprise plan only. No supplied source confirms ISO 27001 or HIPAA BAA for CodeSandbox. The HHS BAA guidance explains when a BAA is required. Ask about report scope, covered services, and contract terms.