API Reference

async modifyConfig(config, context)

Called for any CLI command that loads the next.config.js file to allow modification of the configuration.

Parameters:

• config: The complete Next.js configuration object
• context.phase: The current build phase (see phases)
• context.nextVersion: Version of Next.js being used
• context.projectDir: Absolute path to the Next.js project directory

Returns: The modified configuration object (can be async)

async onBuildComplete(context)

Called after the build process completes with detailed information about routes and outputs.

Parameters:

• context.routing: Object containing Next.js routing phases and metadata
  • routing.beforeMiddleware: Routes executed before middleware (includes header and redirect handling)
  • routing.middlewareMatchers: Middleware matcher definitions for this build, used to decide whether middleware should be invoked for a given request
  • routing.beforeFiles: Rewrite routes checked before filesystem route matching
  • routing.afterFiles: Rewrite routes checked after filesystem route matching
  • routing.dynamicRoutes: Dynamic route matching table
  • routing.onMatch: Routes applied after a successful match (for example immutable static asset cache headers)
  • routing.fallback: Final rewrite fallback routes
  • routing.shouldNormalizeNextData: Whether /_next/data/<buildId>/... URLs should be normalized during matching
  • routing.rsc: Route metadata used for React Server Components routing behavior
• context.outputs: Detailed information about all build outputs organized by type
• context.projectDir: Absolute path to the Next.js project directory
• context.repoRoot: Absolute path to the detected repository root
• context.distDir: Absolute path to the build output directory
• context.config: The final Next.js configuration (with modifyConfig applied)
• context.nextVersion: Version of Next.js being used
• context.buildId: Unique identifier for the current build