Resolving sandbox creation race conditions and duplicate requests

If you're experiencing sandbox creation failures, you may be encountering a race condition caused by duplicate sandbox creation requests being sent simultaneously.

Common Error Messages

You might see errors such as:

• SANDBOX_ALREADY_EXISTS (409) 

• RATE_LIMIT_EXCEEDED (429)

Root Cause

This issue typically occurs when your application makes multiple simultaneous calls to create the same sandbox. Common scenarios include:

• React Strict Mode in development environments, which intentionally runs effects twice

• React hooks triggering multiple times during component re-renders

• Rapid user interactions causing duplicate API calls

Platform-Side Fixes

Our team has implemented several fixes to handle race conditions more gracefully on the platform side. These improvements should prevent most instances of this issue, even when duplicate requests are made.

Preventing Duplicate Requests in Your Code

While the platform now handles most race conditions, you can also prevent duplicate requests in your application.

Primary Solution

The recommended approach is to use createIfNotExists() / create_if_not_exists() instead of create(). This method handles 409 conflicts gracefully by returning the existing sandbox.

const sandbox = await SandboxInstance.createIfNotExists({  
  name: "my-sandbox",  
  image: "blaxel/base-image:latest",  
  memory: 4096,  
  region: "us-pdx-1",  
});

sandbox = await SandboxInstance.create_if_not_exists({  
    "name": "my-sandbox",  
    "image": "blaxel/base-image:latest",  
    "memory": 4096,  
    "region": "us-pdx-1",  
})

In addition, you can also add optional client-side guardrails in your code.

Optional: Add Request Guards

Implement a guard mechanism to prevent multiple simultaneous creation attempts:

• Use an isCreating flag to track when a sandbox creation is in progress

• Check if a sandbox is already being created before making new requests

• Implement proper loading states in your UI

Optional: Handle React Strict Mode

If you're using React Strict Mode in development:

• Consider using useEffect cleanup functions to cancel duplicate requests

• Implement proper dependency arrays to prevent unnecessary re-runs

• Use useRef to track request status across re-renders

What to Do If You Still Experience Issues

If you continue to encounter sandbox creation race conditions after our recent fixes:

1. Note the sandbox ID and timestamp of the error

2. Check if you're making duplicate creation calls in your code

3. Contact support with the specific error details

Our team continues to monitor and improve race condition handling to ensure reliable sandbox creation.