Skip to main content

​
NextAdapter

The NextAdapter interface defines the contract for adapting Next.js builds to the Vercel platform.

​
Properties

​
name
string
required
The name of the adapter. For the Vercel adapter, this is set to "Vercel".
​
onBuildComplete
function
required
Async function called when the Next.js build is complete. Transforms build outputs into Vercel deployment format.

​
onBuildComplete

The onBuildComplete hook is the core function that transforms Next.js build outputs into the Vercel Build Output API format.

​
Parameters

The function receives a single configuration object with the following properties:
​
routing
object
required
Routing configuration from Next.js build including rewrites, redirects, headers, and dynamic routes.
​
config
NextConfig
required
Next.js configuration object including basePath, i18n, images, and other settings.
​
buildId
string
required
Unique identifier for the current build.
​
outputs
object
required
Collection of all build outputs categorized by type.
​
distDir
string
required
Absolute path to the .next build directory.
​
repoRoot
string
required
Absolute path to the repository root directory.
​
projectDir
string
required
Absolute path to the Next.js project directory.
​
nextVersion
string
required
Version string of Next.js being used (e.g., “14.1.0”).

​
Return value

Returns a Promise<void> that resolves when all build outputs have been processed and written to the Vercel output directory.

​
Behavior

The onBuildComplete hook performs the following operations:
  1. Creates the Vercel output directory at {distDir}/output
  2. Processes public files and static outputs
  3. Handles Edge Functions and Node.js functions
  4. Processes middleware if present
  5. Handles prerender outputs for ISR/SSG pages
  6. Generates the routing configuration
  7. Writes the final config.json file
import type { NextAdapter } from 'next';

const myAdapter: NextAdapter = {
  name: 'Vercel',
  async onBuildComplete({
    routing,
    config,
    buildId,
    outputs,
    distDir,
    repoRoot,
    projectDir,
    nextVersion,
  }) {
    // Transform Next.js build outputs to Vercel format
    const vercelOutputDir = path.join(distDir, 'output');
    await fs.mkdir(vercelOutputDir, { recursive: true });
    
    // Process outputs...
  },
};

export = myAdapter;

​
Notes

  • The adapter handles both Node.js and Edge runtime outputs
  • Middleware is supported for both runtimes
  • Static files are optimized with content-type overrides
  • i18n configuration is transformed into Vercel wildcard routing
  • The adapter preserves ISR and PPR (Partial Prerendering) configurations

Build docs developers (and LLMs) love

Get started for freeTalk to us