Blaxel vs Koyeb for persistent AI agent sandboxes

Your coding agent ends a session with a cloned repository and installed dependencies. It also leaves a running development server. The user returns the next morning. If the platform discards that environment, the agent must rebuild everything before responding.

That rebuild cycle is central to the Blaxel versus Koyeb decision. Blaxel is the infrastructure foundation for autonomous agents. Its sandboxes preserve filesystem and memory state during standby. Koyeb is a serverless platform for deploying global applications. Its sandbox product remains in public preview.

Blaxel fits agents whose state must survive between sessions. Koyeb fits teams consolidating GPU inference with application services and databases. This comparison covers lifecycle persistence, platform breadth, and pricing structure.

TL;DR:

• Blaxel for stateful agents: Blaxel preserves sandbox filesystem and memory in perpetual standby with sub-25ms resume and zero idle compute cost.
• Koyeb for global app stacks: Koyeb pairs serverless web deployment with GPU inference, managed Postgres, and a built-in global CDN.
• Shared microVM isolation: Both platforms use microVMs for hardware-enforced tenant boundaries, but differ in the lifecycle built around them.
• Preview status matters: Koyeb Sandboxes remain in public preview. Factor in potential breaking changes before production use.
• Decision driver: Choose based on whether session persistence or platform breadth matters more for your agent workload.

What is Koyeb?

Koyeb is a serverless platform for web services, workers, cron jobs, and managed Postgres. It deploys applications across six core regions. Teams can choose multiple regions during deployment.

A built-in global content delivery network routes traffic near users across Koyeb services. Applications run inside lightweight virtual machines on bare-metal servers. Koyeb also supports scale-to-zero for general application services. That combination suits globally distributed web applications with variable traffic.

On February 17, 2026, Koyeb joined Mistral AI. Koyeb expects to become a core part of Mistral Compute. Its stated focus includes inference, sandboxes, and serverless Model Context Protocol (MCP) workloads.

Koyeb Sandboxes isolate AI-generated and untrusted code inside microVM environments. They entered public preview on November 21, 2025, with a Python SDK. A JavaScript SDK followed in December 2025.

What is Blaxel?

Blaxel is the infrastructure foundation for autonomous agents. Sandboxes run on a forked Firecracker microVM runtime built for agent workloads. Each sandbox has a hardware-enforced kernel boundary for executing untrusted code. Blaxel's default hybrid filesystem uses a read-only base on host storage. Its writable layer uses a RAM-based filesystem. Normal writes therefore go to memory rather than durable disk.

The platform spans compute and storage. Compute includes Sandboxes and Batch Jobs. Storage includes Volumes and Agent Drive, which is in private preview. Agent Drive shares context and artifacts across agents and sessions. Blaxel also supports custom domains and proxy secrets injection. Dedicated egress gateways are available in private preview. These networking features complement the compute and storage primitives without defining the platform's main comparison angle.

Blaxel is a first-class sandbox provider in the OpenAI Agents SDK. The SDK builds on OpenAI's Codex harness. Blaxel Sandboxes handle the execution layer beneath that harness. For persistent coding agents, the main purchasing case remains lifecycle behavior. Sandboxes can remain in standby indefinitely while retaining filesystem and memory state. Volumes provide durable storage when long-term persistence requires stronger guarantees.

Head-to-head feature comparison

The comparison separates sandbox lifecycle behavior from general application scale-to-zero.

Published latency figures describe different lifecycle operations. Blaxel reports sandbox resume from preserved standby state. Koyeb's Light Sleep applies to Services scale-to-zero rather than the Sandbox SDK.

An independent sandbox benchmark measured Blaxel at 0.40 seconds median from creation to first command. Creation and resume are different operations. Test both platforms using the same repository, dependencies, region, and command sequence.

When Blaxel is the better choice

Blaxel's stack exists to run agent code. That purpose appears most clearly in four recurring scenarios.

• Coding agents with live previews: A preserved environment avoids cloning repositories and rebuilding dependencies after every session gap. Preview processes can return with the sandbox state.
• Pull request review agents: Reviews arrive intermittently throughout the day. Standby keeps repository state available without billing active compute throughout every idle period.
• Idle-heavy workloads: Build0 reduced costs by 80% after moving to Blaxel. Network-based shutdown moves disconnected sandboxes into standby after 15 seconds of inactivity.
• Long-running user workspaces: Perpetual standby supports projects that users revisit over days or weeks. Volumes handle data requiring durable long-term retention.

All four cases pair expensive environment setup with unpredictable session gaps. Preserving state removes repeat setup from both user latency and compute consumption.

When Koyeb may fit better

Koyeb is stronger when code execution belongs inside a broader global application. That strength appears most clearly in four recurring scenarios.

• Globally distributed web applications: Serverless web deployment pairs with integrated edge delivery. Teams place services across regions at deployment time, and the global CDN routes requests near users.
• GPU training and inference: Koyeb offers GPU instances billed per second, including H100, H200, and B200 hardware. GPU sandboxes are also supported, while Blaxel publishes no GPU sandbox instances and remains focused on CPU-based agent code execution.
• Multi-service application stacks: Koyeb hosts web services, workers, cron jobs, and managed Postgres. An encrypted private service mesh connects application services inside a single platform.
• Polyglot build pipelines: The build system supports Ruby, PHP, Java, Scala, and other languages, and teams can deploy arbitrary Docker images. Blaxel ships first-class SDKs for Python, TypeScript, and Go, while Ruby, Java, and Rust teams integrate through its REST API.

Koyeb therefore offers broader language and GPU coverage for general application stacks. Teams running model training or self-hosted GPU inference need another provider when standardizing on Blaxel.

Pricing comparison

A reliable pricing comparison requires the same workload rather than mismatched instance labels. For a May 21, 2026 evaluation, use a baseline of 1 vCPU, 2 GB of memory, 10 GB of storage, and one active hour per day across seven days. Keep the repository, region, runtime, and idle intervals identical.

Koyeb bundles CPU and memory in instance configurations, while Blaxel meters usage through sandbox tiers and usage-based pricing. If either provider lacks an exact baseline configuration, request the nearest equivalent and document the difference.

For Koyeb, record the selected instance, active runtime, sleep behavior, storage, region, and plan fee. Per-second billing reduces active compute charges when services scale down.

Resuming a discarded environment can still add startup work to the next request. For Blaxel, record the selected sandbox tier, active runtime, snapshot storage, and any add-ons. Standby removes active compute charges while preserving sandbox state. Durable files should use Volumes rather than relying only on standby snapshots.

Blaxel publishes its pricing in three parts:

• Free: Blaxel offers 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: Blaxel offers email support, live Slack support, and HIPAA compliance as add-ons.

Compare both providers over the same seven-day or 30-day workload window. Include rebuild commands, package downloads, storage, idle intervals, and subscription fees in the total.

Key differentiators and objection handling

Platform engineers and CTOs often raise two questions about this comparison. The first concerns isolation. The second concerns product direction and production commitments.

"Koyeb also runs microVMs, so isolation is equivalent"

Both platforms place hardware-enforced boundaries around untrusted code. Koyeb uses Kata Containers to manage Cloud Hypervisor microVMs. Blaxel uses a forked Firecracker runtime for each sandbox.

Both approaches provide stronger tenant separation than sharing a host kernel directly. The larger difference concerns the lifecycle built around each boundary. Blaxel designed its sandbox runtime around autonomous agent sessions. Standby captures filesystem state, memory state, and running processes. Reconnection restores that preserved environment instead of provisioning a fresh workspace.

Koyeb's Services product uses scale-to-zero for general application workloads. Deep Sleep re-provisions an environment after inactivity. Light Sleep uses snapshots to reduce wake latency and remains in public preview. These features belong to Koyeb Services, not its Sandbox lifecycle interface.

A third-party assessment describes cold starts as a scale-to-zero tradeoff across Docker-based platform services. Edge routing reduces network distance after an instance becomes available. It doesn't remove the startup work required by a discarded application instance. Isolation technology alone therefore doesn't determine session continuity.

Evaluate which product preserves the exact files, processes, and memory your agent needs. Then measure the complete wake path rather than comparing architecture labels.

"Which roadmap can I plan three years around?"

Mistral's backing gives Koyeb a clear strategic parent and a broader compute roadmap. Koyeb says its platform will continue operating. It also expects deeper integration with Mistral Compute across inference, sandboxes, and serverless MCP workloads. Koyeb Sandboxes remain in public preview.

Public preview products can change interfaces, quotas, pricing, or service commitments before general availability. That status doesn't make the product unsuitable for testing. It changes what buyers should require before a production dependency forms. Blaxel's roadmap remains centered on autonomous agent infrastructure.

Its current primitives cover Sandboxes, Batch Jobs, Volumes, and Agent Drive in private preview. The OpenAI Agents SDK integration also provides an external validation point for coding-agent execution.

Before choosing either provider, request commitments that match your production risk:

• Availability terms: Ask for the applicable service-level agreement and its credit schedule. Confirm whether the agreement covers the exact sandbox product.
• Lifecycle guarantees: Document expected state retention, deletion behavior, and recovery procedures. Test those guarantees under failures and regional disruptions.
• Pricing protections: Record current plan fees, usage dimensions, support charges, and notice periods for material pricing changes.
• Migration path: Export templates, dependency manifests, repositories, and durable data. Confirm that another environment can reconstruct the workload.

These checks matter more than broad roadmap language. Written commitments let engineering leaders compare vendor risk against the cost of maintaining an internal platform.

How to evaluate Blaxel vs Koyeb for persistent AI agent sandboxes

Evaluate both platforms with one representative workflow and the same test inputs. The process should expose differences in setup, state restoration, latency, and total workload cost.

1. Configure equivalent workflows

Start with one representative agent workflow. Use the same repository, dependency lockfiles, environment variables, network calls, and user interaction sequence. Run the workload in the nearest comparable region on each platform.

For coding agents, include repository cloning, package installation, development server startup, and preview validation. For review agents, test repeated access to the same repository state. For data analysis agents, verify cached packages, generated files, and in-memory processes.

Use the Blaxel product stack and Koyeb's product documentation to configure equivalent tests. This setup keeps repository contents and workload behavior consistent, so platform lifecycle differences remain visible.

Record each configuration in a worksheet before running the test. Include the provider, product, region, CPU, memory, storage, image, runtime version, and attached services. Add fields for the repository commit, lockfile checksum, environment variables, exposed ports, and startup command. Exclude secret values, but confirm that both environments receive the same secret names and permissions.

Capture the time required for cloning, dependency installation, server startup, and the first successful preview response. Save command output and process lists after setup. Those records establish whether later differences come from the platform lifecycle or from mismatched application configuration. They also make each test repeatable after SDK, image, or platform updates.

2. Measure lifecycle behavior and cost

Measure four lifecycle stages. First, record initial environment creation. Next, record the first command after an idle period. Then verify filesystem, memory, and process state. Finally, calculate total costs across active and inactive periods. Blaxel sandboxes can remain in standby indefinitely. They preserve filesystem and memory state, but standby isn't a durable-storage guarantee.

Use Volumes when data must persist independently from the sandbox lifecycle. Koyeb combines global application deployment with sandbox execution and GPU infrastructure. That model fits web stacks needing integrated services, edge delivery, and inference. Keep Koyeb Services scale-to-zero measurements separate from Koyeb Sandbox lifecycle tests.

Use several idle intervals that reflect the production workload, such as a short pause, an overnight gap, and a multi-day break. For every interval, record the transition entered, wake request time, first successful command time, and first healthy preview response. Verify repository changes, generated files, package caches, process identifiers, listening ports, and in-memory application state.

Note whether any process restarts or rebuild commands were required. The worksheet should also track active seconds, inactive seconds, storage consumed, package downloads, plan fees, and support charges. Compare results in one worksheet. The decision should follow measured state fidelity, latency, platform fit, and total workload cost. Sign up free to run the Blaxel side of this test with up to $200 in credits.

FAQs about Blaxel vs Koyeb for persistent AI agent sandboxes

These answers address persistence, isolation, product direction, and enterprise compliance for both platforms.

Can a Koyeb sandbox persist state between agent sessions?

Koyeb Sandboxes maintain an isolated environment during their configured lifecycle. Koyeb also provides lifecycle management controls for those environments. Teams should distinguish that sandbox lifecycle from Koyeb Services scale-to-zero, which manages general application instances. The practical persistence question concerns which state survives the exact transition your workload uses.

Filesystem contents, memory, running processes, and attached storage are separate state categories. A platform may preserve one category while recreating another. Testing only whether a file remains can miss a stopped development server or an emptied in-memory cache.

Blaxel standby captures filesystem state, memory state, and running processes automatically. The sandbox can remain dormant indefinitely, although Blaxel doesn't guarantee standby as durable long-term storage. Volumes provide the appropriate primitive for data that must outlive a sandbox failure or deletion.

For Koyeb, create a representative sandbox and install real dependencies. Start the same background processes used in production. Let the environment pass through every intended idle and lifecycle transition.

Then reconnect and verify files, process identifiers, open ports, package caches, and generated artifacts. Repeat that test after configuration changes and platform updates. The result determines whether Koyeb's lifecycle behavior meets your session model. Documentation labels alone can't replace a state-by-state validation of the actual agent workflow.

Do Blaxel and Koyeb both use microVM isolation?

Yes. Koyeb runs workloads in Cloud Hypervisor microVMs managed through Kata Containers. Blaxel runs each sandbox in a separate microVM using a forked Firecracker runtime. Both create a kernel boundary around workloads executing AI-generated or untrusted code.

MicroVM isolation matters because each workload receives its own kernel boundary. Traditional containers share the host kernel, even when they isolate processes and filesystems. For arbitrary code execution, a separate kernel reduces the paths available to reach neighboring tenants or host resources.

The two platforms still make different architectural choices around that isolation layer. Koyeb uses its microVM infrastructure across a broader serverless application platform. That platform includes web services, workers, databases, GPU instances, and globally distributed delivery. Blaxel uses Firecracker microVMs as the execution foundation for autonomous agents.

Its sandbox lifecycle adds preserved standby state around those environments. The platform also connects sandboxes with Volumes and Agent Drive for different storage requirements. During evaluation, don't stop at the term "microVM." Review tenant boundaries, image controls, secret handling, network policies, logging, and incident response.

Run adversarial tests using the same code patterns your agents generate. Isolation technology establishes the boundary, while platform controls determine how teams operate that boundary safely.

How does the Mistral AI acquisition affect Koyeb customers?

Koyeb states that the platform will continue operating after joining Mistral AI. It expects Koyeb technology to become part of Mistral Compute. The announced focus includes inference, sandboxes, and serverless MCP workloads. For existing customers, the acquisition provides strategic backing and tighter alignment with Mistral's infrastructure plans.

It can also influence product priorities as Koyeb becomes part of a larger compute portfolio. Neither outcome provides a substitute for product-specific contractual commitments. Koyeb Sandboxes remain in public preview.

Teams considering production use should ask which support terms apply today. They should also request the planned general availability criteria, migration policy, deprecation notice period, and service-level agreement coverage.

Koyeb currently lists a Starter plan for users with a valid payment method. Buyers should verify current pricing during evaluation rather than relying on acquisition commentary. Plan availability, included credits, and resource limits can change independently from technical product direction.

Existing customers should export their service definitions and maintain reproducible deployment files. They should also document dependencies on Koyeb-specific networking, databases, regions, and lifecycle behavior. Those steps reduce migration risk regardless of ownership changes.

The acquisition matters strategically, but workload portability and written service terms remain the practical safeguards.

Which platform is stronger on compliance for enterprise deals?

Blaxel documents SOC 2 Type II and ISO 27001:2022 certifications. It also offers Health Insurance Portability and Accountability Act compliance through a Business Associate Agreement (BAA). Those controls support procurement for teams executing sensitive or regulated code.

Koyeb lists ISO 27001 and SOC 2 among its platform credentials. Enterprise buyers should request the current reports, certification scopes, covered services, and control periods directly from Koyeb. The same diligence should apply to Blaxel rather than relying only on marketing summaries.

Compliance strength depends on the workload and contract, not the number of badges. Confirm whether each report covers sandboxes, storage, networking, support access, and relevant subprocessors. Review data residency, encryption, deletion, identity controls, audit logging, and incident notification terms.

Healthcare buyers should verify whether a BAA covers every service handling protected health information. Security teams should map vendor controls against their own threat model. Procurement should also confirm breach notification windows, audit rights, penetration-testing evidence, and subcontractor obligations.

Run this review before the technical proof of concept ends. Missing documents can extend procurement even when the platform passes performance testing. A structured security questionnaire and contract review provide a fairer comparison than inferring gaps from public pricing pages.