Route Runtime

3 min read

Choose the execution runtime, regions, and maximum duration for dynamic pages and API routes. Farm uses one contract across file routes, programmatic routes, layouts, and routeRules.

File pages

Export the controls next to the page that owns them. No wrapper or additional route file is required.

src/app/reports/page.tsx

export const runtime = "node";export const regions = ["iad1", "fra1"];export const maxDuration = 30;export default async function ReportsPage() {  const reports = await getReports();  return <Reports reports={reports} />;}

maxDuration is measured in seconds. Region identifiers belong to the selected deployment provider; Farm validates the portable shape and lets the adapter interpret the identifiers.

API routes

API files use the same exports.

src/app/api/reports/route.ts

export const runtime = "node";export const regions = ["fra1"];export const maxDuration = 15;export async function GET() {  return Response.json(await getReports());}

Layouts do not wrap API handlers, so API routes inherit matching routeRules, then apply their own named exports.

Layout defaults

A layout sets defaults for pages below its segment. The complete layout tree executes in the runtime selected for the final page.

src/app/admin/layout.tsx

import type { LayoutProps } from "@farmjs/core";export const runtime = "node";export const regions = ["fra1"];export const maxDuration = 60;export default function AdminLayout({ children }: LayoutProps) {  return <main>{children}</main>;}

A child can override only the value it needs:

src/app/admin/analytics/page.tsx

export const maxDuration = 20;export default function AnalyticsPage() {  return <Analytics />;}

Farm resolves controls from lowest to highest precedence:

Broad matching routeRules
More-specific matching routeRules
Parent layouts
Nearest layout
page.tsx or API route.ts

Reset inherited values

Use "auto" when a route should return to the deployment provider's default instead of inheriting a layout or rule.

export const runtime = "auto";export const regions = "auto";export const maxDuration = "auto";

An omitted export inherits. An explicit "auto" resets.

Programmatic routes

The same fields are typed on every programmatic primitive.

src/farm.routes.tsx

import { defineRoutes } from "@farmjs/core";import { ReportsPage } from "./features/reports/page";export default defineRoutes(({ page, layout, api }) => [  page("/reports", {    runtime: "node",    regions: ["iad1", "fra1"],    maxDuration: 30,    component: ReportsPage,  }),  layout("/admin", {    runtime: "node",    maxDuration: 60,    component: AdminLayout,  }),  api("/api/reports", {    runtime: "node",    regions: ["fra1"],    maxDuration: 15,    GET: async () => Response.json(await getReports()),  }),]);

Route rules

Use route rules when deployment policy belongs to a URL group rather than one source file.

farm.config.ts

import { defineConfig } from "@farmjs/core";export default defineConfig({  routeRules: {    "/api/public/**": {      runtime: "node",      regions: ["iad1"],      maxDuration: 10,    },    "/admin/**": {      runtime: "node",      regions: ["fra1"],      maxDuration: 60,    },  },});

Page, API, and layout values override matching rules. Rules still apply to generated integration endpoints that do not have a page file.

Deployment behavior

Farm writes the normalized result to .farm/route-runtime-manifest.json on production builds. Custom deployment adapters can consume this manifest instead of parsing source files.

Preset family	Runtime accepted	`regions`	`maxDuration`
`vercel`	`auto`, `node`	Enforced per generated function	Enforced per generated function
Cloudflare presets	`auto`, `edge`	Preserved for adapters	Preserved for adapters
`netlify`	`auto`, `node`	Preserved for adapters	Preserved for adapters
`netlify-edge`	`auto`, `edge`	Preserved for adapters	Preserved for adapters
`node-server`	`auto`, `node`	Preserved in the manifest	Preserved in the manifest
Custom preset	Adapter-defined	Preserved in the manifest	Preserved in the manifest

For Vercel Node builds, Farm creates one Build Output API function per distinct region/duration policy and routes matching requests to it. Routes using provider defaults continue using the base function.

A production build fails when a dynamic route requests an incompatible runtime, such as runtime = "edge" with the Node-based vercel preset or runtime = "node" with a Cloudflare Worker preset. Farm warns when a valid runtime target cannot map a region or duration hint, while keeping the value available in the manifest.

Farm's current Vercel adapter emits Node functions. Use a supported Edge preset such as cloudflare-module or netlify-edge for runtime = "edge"; do not treat a Vercel region identifier as a portable Edge guarantee.

Static routes and development

Static pages are generated during the build and do not have a request-time function. Runtime, region, and duration controls therefore do not change how a fully static page is served.

The local development server runs in Node so one process can provide HMR and route discovery. Runtime compatibility and provider output are enforced by farm build, which is the command CI should run before deployment.

Practical guidance

Keep functions close to their database, not necessarily close to every browser.
Set maxDuration high enough for normal streaming responses but low enough to cap runaway work.
Use edge only when the complete page, layout tree, middleware, and dependencies support Web APIs without Node-only modules.
Prefer layout defaults for coherent application areas and route rules for generated or cross-cutting endpoints.
Avoid configuring static pages unless the same policy also applies when the page becomes dynamic later.