Troubleshooting Build Error: "Build step did not complete within the maximum of 45 minutes"

Builds that approach or exceed the 45-minute limit usually indicate that too much work is happening during build time.

This guide explains the most common causes of 45-minute build timeouts on Vercel and provides practical strategies to identify bottlenecks, reduce build-time work, and keep deployments fast and reliable.

Vercel enforces a maximum Build Step duration of 45 minutes. When that limit is reached, the Build Step is interrupted and the deployment will fail.

To more easily troubleshoot build timeouts, you can wrap your existing build command with a timeout command which will kill builds before they timeout. This method ensures that your builds are terminated gracefully, preventing unnecessary resource usage: How can I set a custom build timeout?

If you’re blocked by build timeouts and need a workaround, or if you prefer bypassing Vercel’s build step altogether, you can “prebuild” your project by building it locally and deploying the prebuilt artifacts to Vercel:

• Run vercel build to generate build artifacts.
• Then deploy them with vercel deploy --prebuilt.

Your project may be spending most of its time in a framework build step generating pages/content. Next.js/Gatsby/Nuxt static generation times grow with content volume (pages, routes, localized variants, CMS entries, etc.).

Although there is no upper limit for output files created during a build, you can expect longer build times as a result of having many thousands of output files (100,000 or more, for example). At this point, builds can get much slower and may exceed 45 minutes.

How to fix

• Reduce the amount of content being generated at build time.
• For Next.js projects, use getStaticPaths (Pages Router) or generateStaticParams (App Router) to control which pages are generated during the build.
  • You can significantly decrease your build times by not pre-rendering any pages during your build and instead generating all static pages on demand. When deployed to Vercel, you can further extend this by pre-rendering pages for only production builds.
  • We also recommend Incremental Static Regeneration (ISR) to pre-render only a subset of pages at build time and generate others on demand. ISR allows you to create or update content without redeploying your site and has three main benefits for developers: better performance, improved security, and faster build times.
    • Better Performance: Static pages can be consistently fast by caching generated pages in every region on Vercel's CDN and persisting files into durable storage.
    • Improved Security: ISR Render Functions are used to generate pages and do not have access to the incoming request, which prevents accidental caching of user data for increased security.
    • Faster Builds: Pages can defer generation on request or through an API instead of during the build, helping keep build times fast as your application grows.

Vercel’s ‘Standard’ build containers are allocated 8192 MB of memory. When projects overrun this, a SIGKILL or OOM error is generally thrown. However, in some instances a build may not get killed promptly and runs until it times out.

How to fix

• To immediately rule out lack of memory capacity, upgrade to the Enhanced build tier and re-deploy your failing deployment. If it succeeds, the culprit was likely due to memory or CPU bottlenecks (see below on CPU-bound deployments for more on this).
• Follow our guide on troubleshooting SIGKILL/OOM errors for detailed steps on reducing memory overhead.

Deployments can become CPU-bound when the build step performs expensive computation (e.g. large bundles, heavy transpilation, image processing, or large file graphs). This can manifest as very long builds or 45-minute timeouts.

Very large deployments (tens of thousands of outputs) can overwhelm build-processing services if work is done in unbounded parallelism. Promise.all() and heavy CPU operations like JSON.stringify() and Buffer.byteLength() can be problematic operations in large deployments when every task is run in parallel.

CPU-bound deployments can also present as logs showing long “Compiling…”, “Bundling…”, “Minifying…”, “Generating server/client bundles…” steps.

How to fix

• Use bounded concurrency by batching CPU-heavy tasks or using p-limit.
• Avoid generating large source maps unless necessary.
• Consider upgrading to a larger build machine
  • For Pro and Enterprise customers, we offer two higher-tier build machines with more vCPUs, memory and disk space than Standard.

If your build can’t use cache (or the cache is invalidated), the deployment need to do full reinstall of node_modules which can dominate build time (especially for large repos/monorepos/native dependencies). This typically presents as logs that look stuck in install for a large chunk of time (“Installing dependencies…”), or when every build behaves like a cold build by downloading/re-installing everything.

This can occur due to cache misses (changed cache key, different branch, Node version changes, package manager changes), large node_modules folders, “expensive” native builds, or from heavy postinstall scripts (downloading browsers, building binaries, etc.).

How to fix

• Ensure you’re caching your builds effectively by keeping your package manager and cache keys stable and consistent.
  • Cache keys can get invalidated by changing root directory, Node version, package manager, or building lots of branches with no warm cache.

• Remove unused dependencies and move optional tooling out of the build path.

• Exclude development dependencies by customizing the install command to skip dev dependencies (e.g. npm install --only=production or yarn install --production). This only works if your build does not require those dev dependencies.

Quality gates are steps that validate correctness and code quality before changes are merged or released.

Common examples include:

• TypeScript type checking
• ESLint or other linting
• Unit, integration, or end-to-end tests
• Storybook builds
• Documentation generation
• Large code generation steps (OpenAPI clients, GraphQL artifacts, SDKs, etc.)

Many of these tasks are CPU-bound and scale poorly with repository size, don’t contribute to deployment output, and are redundant if the same checks can be run elsewhere. They consume build time that could otherwise be spent generating deployable artifacts.

Some quality gates don’t need to be run during build time and can be moved to dedicated CI (Continuous Integration) systems such as GitHub Actions, which are more appropriate for validation work and don’t enforce the same timeout limits.

How to fix

• Move validation work out of the Vercel Build Step into CI
  • Run linting, tests, and type checking in CI instead of during vercel build
• Keep your deployment build focused on generating output artifacts
• Ensure that you’re not doubling up a check that may already exist in your CI
• For Next.js projects, you can disable ESLint and TypeScript type checking during build time if your project already runs them in CI. This can reduce help reduce total build time:

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// next.config.js
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// Disabling linting during build
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module.exports = {
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  eslint: {
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    ignoreDuringBuilds: true,
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  },
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}
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// next.config.js
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// Disabling TypeScript type checking during build
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module.exports = {
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  typescript: {
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    ignoreBuildErrors: true,
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  },
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}

Deployments can slow down or time out if your project contains a large number of Vercel Functions. On Vercel, each function is built independently, and maintains its own build cache, which means build time increases as the number and size of functions grows.

A higher number of functions means more individual build steps, and larger functions take longer to bundle, optimize, and cache.

This issue commonly presents in applications with many routes and dynamic segments and can present as:

• Build duration increasing as more routes or API endpoints are added
• Logs show repeated steps for function compilation and bundling
• Deployments that previously succeeded begin timing out as the application grows
• Small code changes trigger long rebuilds due to the number of functions involved

How to fix

• Reduce the number of generated functions where possible
• Consolidate related API routes into a single handler
• Avoid creating one function per minor route variation when shared logic is possible
• Prefer parameterized routes over many static route files
• Use a single runtime when edge execution is not required
• Avoid using large shared dependencies across many functions

If your project makes network requests during build time with no explicit timeouts, this can cause build timeouts if the endpoint or host can’t be reached, or if your request gets blocked by the host.

Network calls are commonly used during build time to:

• Fetch CMS content
• Call internal or external APIs
• Connect to databases
• Download large assets or binaries
• Validate credentials or licenses

If your calls don’t have timeouts, retry indefinitely, or wait for input, the network call may stall. This can also occur if you get rate-limited by a service.

How to fix

• Add explicit timeouts to all build-time network calls to prevents the build from hanging indefinitely, and have visible logging
• Add bounded retries if retries are required, and avoid infinite retries
• Use a small, fixed number of retries with backoff

• If an upstream service is unavailable, fail fast
• Avoid network calls during build time where possible by moving data fetching to runtime
• For static sites, consider generating only a minimal set of content at build time and deferring the rest to runtime

Build timeouts are rarely caused by a single issue and in most cases occur due to multiple factors compounding over time as your application grows. When builds approach this limit, it usually indicates:

• excessive work happening at build time
• architectural choices that don’t scale with project growth
• validation tasks that belong elsewhere

If your builds are still timing out after applying these principles, don't hesitate to reach out to our support team for further assistance.