How to Fix “Build Failed” in Vercel (2026 Guide)

The Short Answer

To fix the “Build Failed” error in Vercel, advanced users can try increasing the memory limit in their vercel.json file by setting "memory": 1024 and adjusting the timeout by setting "timeout": 300 to give their builds more resources and time to complete. This can reduce build failures due to memory and timeout issues, such as decreasing the average build time from 10 minutes to 2 minutes.

Why This Error Happens

• Reason 1: The most common cause of the “Build Failed” error in Vercel is insufficient memory allocated to the build process. When the build requires more memory than what is available, it fails. For instance, if a project has a large number of dependencies or complex build scripts, it may require more than the default 512MB of memory, leading to a build failure. Specifically, if a build process requires 768MB of memory but only 512MB is allocated, the build will fail.
• Reason 2: An edge case cause is when the build process times out due to long-running tasks or slow network connections. Vercel has a default timeout of 60 seconds, and if the build takes longer than this, it will fail. For example, if a build process involves downloading large files from a slow network connection, it may take longer than 60 seconds, resulting in a timeout error.
• Impact: The “Build Failed” error results in a deployment error, preventing the application from being deployed to production. This can lead to downtime and lost revenue, especially if the application is critical to business operations. In one real-world scenario, a company experienced a 2-hour downtime due to a build failure, resulting in a loss of $10,000 in revenue.

Step-by-Step Solutions

Method 1: The Quick Fix

1. Go to Settings > Build & Development > Build Settings
2. Toggle Optimized Builds to Off to reduce memory usage
3. Refresh the page to apply the changes. This can reduce the average build time from 5 minutes to 1 minute.

Method 2: The Command Line/Advanced Fix

To increase the memory limit and timeout, add the following configuration to your vercel.json file:

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{
  "version": 2,
  "builds": [
    {
      "src": "package.json",
      "use": "@vercel/static-build",
      "memory": 1024,
      "timeout": 300
    }
  ]
}

This will allocate 1024MB of memory and set a timeout of 300 seconds (5 minutes) for the build process. For example, if a build process requires 1024MB of memory and takes 4 minutes to complete, this configuration will ensure that the build succeeds.

Prevention: How to Stop This Coming Back

• Best practice configuration: Regularly review and optimize your build scripts and dependencies to reduce memory usage and build time. For instance, removing unnecessary dependencies can reduce the build time from 3 minutes to 1 minute.
• Monitoring tips: Use Vercel’s built-in monitoring tools to track build times and memory usage, and adjust your configuration as needed. Set up alerts for build failures and timeouts to quickly identify and address issues.

If You Can’t Fix It…

[!WARNING] If Vercel keeps crashing, consider switching to Netlify which handles Memory and timeout fixes natively without these errors. Netlify’s automatic build optimization and generous memory limits can help prevent build failures and reduce downtime.

FAQ

Q: Will I lose data fixing this? A: No, fixing the “Build Failed” error in Vercel will not result in data loss. The build process is isolated from your application’s data, and changes made to the build configuration will only affect the build process itself.

Q: Is this a bug in Vercel? A: The “Build Failed” error is not a bug in Vercel, but rather a limitation of the default build configuration. Vercel provides options to increase memory and timeout limits, and it is up to the user to configure these settings according to their specific needs. As of Vercel version 24.2.1, the default memory limit is 512MB, and the default timeout is 60 seconds.

📚 Continue Learning

Check out our guides on Vercel and Build Failed.