jsschools

runtime (route segment config)

Selects the Node.js or Edge runtime for a route segment.

Since Next 13 (App Router) Spec ↗

Syntax

export const runtime = 'nodejs' | 'edge'

Returns

string — The execution runtime for the segment.

Examples

// Run this Route Handler on the Edge runtime
export const runtime = 'edge'

export async function GET() {
  return Response.json({ region: process.env.VERCEL_REGION })
}

// Explicitly use the Node.js runtime (default)
export const runtime = 'nodejs'

export default async function Page() {
  const fs = await import('node:fs/promises')
  const data = await fs.readFile('./data.json', 'utf8')
  return <pre>{data}</pre>
}

Notes

Default is `nodejs` (full Node APIs, larger cold start). `edge` uses the lightweight Edge runtime: faster startup and global execution but a limited Web-only API surface (no native Node modules). Choose `edge` for tiny, latency-sensitive handlers. Exported from `page.js`/`layout.js`/`route.js`.

See also