diff --git a/packages/kit/src/core/env.js b/packages/kit/src/core/env.js
index c70f50502bb7..46042008c29f 100644
--- a/packages/kit/src/core/env.js
+++ b/packages/kit/src/core/env.js
@@ -112,12 +112,13 @@ export async function load_explicit_env(kit, file, root, mode) {
 }
 
 /**
- * Creates the `__sveltekit/env` module
+ * Creates the `<sveltekit:generated>/env/config.js` module
  * @param {Record<string, EnvVarConfig<any> | undefined> | null} variables
  * @param {Record<string, string>} env
  * @param {string | null} entry
+ * @param {boolean} is_dev
  */
-export function create_sveltekit_env(variables, env, entry) {
+export function create_sveltekit_env(variables, env, entry, is_dev) {
 	const imports = entry
 		? [
 				`import { variables } from ${JSON.stringify(entry)};`,
@@ -170,33 +171,25 @@ export function create_sveltekit_env(variables, env, entry) {
 			}`
 	];
 
-	return blocks.join('\n\n');
-}
+	if (is_dev) {
+		// In dev, initialise the env immediately. Tools like `vite-node` load modules
+		// through the Vite config but don't run the SvelteKit dev server, which is what
+		// normally calls `set_env`. Without this, dynamic env vars imported from
+		// `$app/env/public` and `$app/env/private` would be `undefined` in such contexts.
+		/** @type {Record<string, string>} */
+		const dev_env = {};
+		for (const name of Object.keys(variables ?? {})) {
+			if (name in env) dev_env[name] = env[name];
+		}
 
-/**
- * @param {Record<string, EnvVarConfig<any> | undefined> | null} variables
- * @param {Record<string, string>} env
- */
-export function create_sveltekit_env_dev(variables, env) {
-	// In dev, initialise the env immediately. Tools like `vite-node` load modules
-	// through the Vite config but don't run the SvelteKit dev server, which is what
-	// normally calls `set_env`. Without this, dynamic env vars imported from
-	// `$app/env/public` and `$app/env/private` would be `undefined` in such contexts.
-	/** @type {Record<string, string>} */
-	const dev_env = {};
-	for (const name of Object.keys(variables ?? {})) {
-		if (name in env) dev_env[name] = env[name];
+		blocks.push(`set_env(${devalue.uneval(dev_env)});`);
 	}
 
-	return [
-		`import { set_env } from './config.js';`,
-		`set_env(${devalue.uneval(dev_env)});`,
-		`export * from './config.js';`
-	].join('\n\n');
+	return blocks.join('\n\n');
 }
 
 /**
- * Creates the `__sveltekit/env/private` module
+ * Creates the `<sveltekit:generated>/env/private/server.js` module
  * @param {Record<string, EnvVarConfig<any>> | null} variables
  * @param {Record<string, string>} env
  */
@@ -223,11 +216,11 @@ export function create_sveltekit_env_private(variables, env) {
 
 	handle_issues(issues);
 
-	return `import { dynamic_private_env as env } from '__sveltekit/env';\n\n${exports.join('')}`;
+	return `import { dynamic_private_env as env } from '../config.js';\n\n${exports.join('')}`;
 }
 
 /**
- * Creates the `__sveltekit/env/public/*` modules
+ * Creates the `<sveltekit:generated>/env/public/*` modules
  * @param {Record<string, EnvVarConfig<any>> | null} variables
  * @param {Record<string, string>} env
  * @param {string} prelude
@@ -259,7 +252,7 @@ export function create_sveltekit_env_public(variables, env, prelude) {
 }
 
 /**
- * Creates the `__sveltekit/env/service-worker` module used in production. When an app uses
+ * Creates the `<sveltekit:generated>/env/service-worker.js` module used in production. When an app uses
  * dynamic public env vars, they're loaded at runtime via an import of the prerendered
  * `env.js`. If there are none, values are inlined.
  * @param {Record<string, EnvVarConfig<any>> | null} variables
@@ -297,7 +290,7 @@ export function create_sveltekit_env_service_worker(
 }
 
 /**
- * Creates the `__sveltekit/env/service-worker` module used in development
+ * Creates the `<sveltekit:generated>/env/service-worker.js` module used in development
  * @param {Record<string, EnvVarConfig<any>> | null} variables
  * @param {Record<string, string>} env
  * @param {string} version
diff --git a/packages/kit/src/core/postbuild/analyse.js b/packages/kit/src/core/postbuild/analyse.js
index dad39d6bca64..dde9f386195e 100644
--- a/packages/kit/src/core/postbuild/analyse.js
+++ b/packages/kit/src/core/postbuild/analyse.js
@@ -54,7 +54,7 @@ async function analyse({
 
 	// `set_env` lives in a separate module that imports the user's `src/env` config. We import it
 	// *after* `set_building()` so that `building`-dependent expressions resolve correctly
-	/** @type {typeof import('__sveltekit/env')} */
+	/** @type {typeof import('<sveltekit:generated>/env/config.js')} */
 	const { set_env } = await import(pathToFileURL(`${server_root}/server/env.js`).href);
 	set_env(env);
 
diff --git a/packages/kit/src/core/postbuild/prerender.js b/packages/kit/src/core/postbuild/prerender.js
index aeede61deec8..a32690448fb0 100644
--- a/packages/kit/src/core/postbuild/prerender.js
+++ b/packages/kit/src/core/postbuild/prerender.js
@@ -62,7 +62,7 @@ async function prerender({
 
 	// `set_env` and `Server` live in modules that import the user's `src/env` config. We import them
 	// *after* `set_building()` so that `building`-dependent expressions resolve correctly
-	/** @type {typeof import('__sveltekit/env')} */
+	/** @type {typeof import('<sveltekit:generated>/env/config.js')} */
 	const { set_env } = await import(pathToFileURL(`${out}/server/env.js`).href);
 	set_env(env);
 
diff --git a/packages/kit/src/exports/vite/index.js b/packages/kit/src/exports/vite/index.js
index 86e18b51d7a0..ace5deebe27f 100644
--- a/packages/kit/src/exports/vite/index.js
+++ b/packages/kit/src/exports/vite/index.js
@@ -94,7 +94,8 @@ const enforced_config = {
 	resolve: {
 		alias: {
 			$app: true,
-			$env: true
+			$env: true,
+			'<sveltekit:generated>': true
 		}
 	}
 };
@@ -455,6 +456,10 @@ function kit({ svelte_config }) {
 							{ find: '__SERVER__', replacement: `${generated}/server` },
 							{ find: '$app', replacement: `${runtime_directory}/app` },
 							{ find: '$env', replacement: `${runtime_directory}/env` },
+							{
+								find: '<sveltekit:generated>',
+								replacement: `${out_dir}/generated/${is_build ? 'build' : 'dev'}`
+							},
 							{
 								find: '__sveltekit/server',
 								replacement: `${runtime_directory}/server/internal.js`
@@ -504,7 +509,7 @@ function kit({ svelte_config }) {
 							// because they for example use rolldown.build with `platform: 'browser'`
 							'esm-env',
 							// This forces `$app/*` modules to be bundled, since they depend on
-							// virtual modules like `__sveltekit/env` (this isn't a valid bare
+							// generated modules like `<sveltekit:generated>/env/config.js` (this isn't a valid bare
 							// import, but it works with vite-node's externalization logic, which
 							// uses basic concatenation)
 							'@sveltejs/kit/src/runtime'
@@ -1063,6 +1068,9 @@ function kit({ svelte_config }) {
 			const new_config = {
 				environments: {
 					serviceWorker: {
+						define: {
+							__SVELTEKIT_PAYLOAD__: kit_global
+						},
 						build: {
 							modulePreload: false,
 							rolldownOptions: {
@@ -1198,7 +1206,7 @@ function kit({ svelte_config }) {
 				// build time, so `env.js` is loaded at runtime. In dev, the
 				// imported module just inlines the current values instead.
 				return {
-					code: `import '__sveltekit/env/service-worker';\n${code}`
+					code: `import '<sveltekit:generated>/env/service-worker.js';\n${code}`
 				};
 			}
 		}
@@ -1231,7 +1239,7 @@ function kit({ svelte_config }) {
 					const server_input = {
 						index: `${runtime_directory}/server/index.js`,
 						internal: `${out_dir}/generated/server/internal.js`,
-						env: '__sveltekit/env',
+						env: '<sveltekit:generated>/env/config.js',
 						['remote-entry']: `${runtime_directory}/app/server/remote/index.js`
 					};
 
@@ -1765,7 +1773,8 @@ function kit({ svelte_config }) {
 						has_explicit_dynamic_public_env &&
 						client_chunks.some(
 							(chunk) =>
-								chunk.type === 'chunk' && chunk.modules[`${out_dir}/generated/env/public/client.js`]
+								chunk.type === 'chunk' &&
+								chunk.modules[`${out_dir}/generated/build/env/public/client.js`]
 						);
 
 					if (kit.output.bundleStrategy === 'split') {
@@ -1965,8 +1974,11 @@ function kit({ svelte_config }) {
 						log.info('Building service worker');
 
 						// mirror client settings that we couldn't set per environment in the config hook
-						builder.environments.serviceWorker.config.define =
-							builder.environments.client.config.define;
+						builder.environments.serviceWorker.config.define = {
+							...builder.environments.client.config.define,
+							...builder.environments.serviceWorker.config.define
+						};
+
 						builder.environments.serviceWorker.config.resolve.alias = [
 							...get_config_aliases(kit, vite_config.root)
 						];
diff --git a/packages/kit/src/exports/vite/plugins/env-vars.js b/packages/kit/src/exports/vite/plugins/env-vars.js
index 45bbd6cfcb77..dfda9efa8f3a 100644
--- a/packages/kit/src/exports/vite/plugins/env-vars.js
+++ b/packages/kit/src/exports/vite/plugins/env-vars.js
@@ -5,7 +5,6 @@ import path from 'node:path';
 import * as sync from '../../../core/sync/sync.js';
 import {
 	create_sveltekit_env,
-	create_sveltekit_env_dev,
 	create_sveltekit_env_private,
 	create_sveltekit_env_public,
 	create_sveltekit_env_service_worker,
@@ -18,7 +17,6 @@ import { s } from '../../../utils/misc.js';
 import { write_if_changed } from '../../../core/sync/utils.js';
 import { hash } from '../../../utils/hash.js';
 import { posixify } from '../../../utils/os.js';
-import { prefixRegex } from '@rolldown/pluginutils';
 
 /**
  * Generate (and, in dev, maintain) a `${outDir}/generated/env/config.js` module
@@ -29,14 +27,10 @@ import { prefixRegex } from '@rolldown/pluginutils';
  * @returns {Plugin}
  */
 export function plugin_env_vars(config, callback) {
-	// grab these values eagerly because they get mutated (TODO stop mutating them)
-	const dir = config.env.dir;
-	const out = config.outDir;
-
 	const version_hash = hash(config.version.name);
 
 	/** @type {string} */
-	let out_dir;
+	let dir;
 
 	/** @type {Record<string, any>} */
 	let env;
@@ -66,71 +60,71 @@ export function plugin_env_vars(config, callback) {
 		deps = synced.deps;
 
 		const vars = synced.variables;
-		const dir = `${out_dir}/generated/env`;
+		callback(vars);
 
 		write_if_changed(
 			`${dir}/config.js`,
 			create_sveltekit_env(
 				vars,
 				env,
-				resolved_entry && posixify(path.relative(dir, resolved_entry))
-			)
-		);
-
-		write_if_changed(`${dir}/config-dev.js`, create_sveltekit_env_dev(vars, env));
-
-		write_if_changed(
-			`${dir}/public/client.js`,
-			create_sveltekit_env_public(
-				vars,
-				env,
-				`import { payload } from ${s(posixify(path.relative(`${dir}/public`, `${runtime_directory}/client/payload.js`)))};\nconst env = payload.env;`
+				resolved_entry && posixify(path.relative(dir, resolved_entry)),
+				!is_build
 			)
 		);
 
 		write_if_changed(
 			`${dir}/public/server.js`,
-			create_sveltekit_env_public(
-				vars,
-				env,
-				`import { rendered_env as env } from '__sveltekit/env';`
-			)
-		);
-
-		write_if_changed(
-			`${dir}/public/service-worker.js`,
-			create_sveltekit_env_public(
-				vars,
-				env,
-				`const env = globalThis.__sveltekit_${version_hash}.env;`
-			)
+			create_sveltekit_env_public(vars, env, `import { rendered_env as env } from '../config.js';`)
 		);
 
 		write_if_changed(`${dir}/private/server.js`, create_sveltekit_env_private(vars, env));
 
-		write_if_changed(
-			`${dir}/service-worker-prod.js`,
-			create_sveltekit_env_service_worker(
-				vars,
-				env,
-				config.version.name,
-				`globalThis.__sveltekit_${version_hash}`,
-				config.paths.base,
-				config.appDir
-			)
-		);
-
-		write_if_changed(
-			`${dir}/service-worker-dev.js`,
-			create_sveltekit_env_service_worker_dev(
-				vars,
-				env,
-				config.version.name,
-				'globalThis.__sveltekit_dev'
-			)
-		);
-
-		callback(vars);
+		if (is_build) {
+			write_if_changed(
+				`${dir}/public/client.js`,
+				create_sveltekit_env_public(
+					vars,
+					env,
+					`import { payload } from ${s(posixify(path.relative(`${dir}/public`, `${runtime_directory}/client/payload.js`)))};\nconst env = payload.env;`
+				)
+			);
+
+			write_if_changed(
+				`${dir}/public/service-worker.js`,
+				create_sveltekit_env_public(
+					vars,
+					env,
+					`const env = globalThis.__sveltekit_${version_hash}.env;`
+				)
+			);
+
+			write_if_changed(
+				`${dir}/service-worker.js`,
+				create_sveltekit_env_service_worker(
+					vars,
+					env,
+					config.version.name,
+					`globalThis.__sveltekit_${version_hash}`,
+					config.paths.base,
+					config.appDir
+				)
+			);
+		} else {
+			write_if_changed(
+				`${dir}/public/client.js`,
+				create_sveltekit_env_public(vars, env, `const { env } = globalThis.__sveltekit_dev;`)
+			);
+
+			write_if_changed(
+				`${dir}/service-worker.js`,
+				create_sveltekit_env_service_worker_dev(
+					vars,
+					env,
+					config.version.name,
+					'globalThis.__sveltekit_dev'
+				)
+			);
+		}
 	}
 
 	return {
@@ -140,11 +134,13 @@ export function plugin_env_vars(config, callback) {
 			resolved_config = c;
 
 			const vite = await import_peer('vite', c.root);
-			env = vite.loadEnv(c.mode, path.resolve(c.root, dir), '');
-
-			out_dir = posixify(path.resolve(c.root, out));
+			env = vite.loadEnv(c.mode, path.resolve(c.root, config.env.dir), '');
 
 			is_build = c.command === 'build';
+
+			dir = posixify(
+				path.resolve(c.root, config.outDir, `generated/${is_build ? 'build' : 'dev'}/env`)
+			);
 		},
 
 		async buildStart() {
@@ -179,37 +175,6 @@ export function plugin_env_vars(config, callback) {
 		async handleHotUpdate(update) {
 			if (!deps.has(update.file)) return;
 			await generate();
-		},
-
-		resolveId: {
-			filter: {
-				id: prefixRegex('__sveltekit/env')
-			},
-			handler(id) {
-				const dir = `${out_dir}/generated/env`;
-
-				if (id === '__sveltekit/env') {
-					return is_build ? `${dir}/config.js` : `${dir}/config-dev.js`;
-				}
-
-				if (id === '__sveltekit/env/private') {
-					return `${dir}/private/server.js`;
-				}
-
-				if (id === '__sveltekit/env/public/server') {
-					return `${dir}/public/server.js`;
-				}
-
-				if (id === '__sveltekit/env/public/client') {
-					return this.environment.name === 'serviceWorker'
-						? `${dir}/public/service-worker.js`
-						: `${dir}/public/client.js`;
-				}
-
-				if (id === '__sveltekit/env/service-worker') {
-					return is_build ? `${dir}/service-worker-prod.js` : `${dir}/service-worker-dev.js`;
-				}
-			}
 		}
 	};
 }
diff --git a/packages/kit/src/runtime/app/env/private/index.js b/packages/kit/src/runtime/app/env/private/index.js
index b3cb5882c213..a8c352f3f5a5 100644
--- a/packages/kit/src/runtime/app/env/private/index.js
+++ b/packages/kit/src/runtime/app/env/private/index.js
@@ -1 +1 @@
-export * from '__sveltekit/env/private';
+export * from '<sveltekit:generated>/env/private/server.js';
diff --git a/packages/kit/src/runtime/app/env/public/client.js b/packages/kit/src/runtime/app/env/public/client.js
index 3a0825440e75..ad816fbc7488 100644
--- a/packages/kit/src/runtime/app/env/public/client.js
+++ b/packages/kit/src/runtime/app/env/public/client.js
@@ -1 +1 @@
-export * from '__sveltekit/env/public/client';
+export * from '<sveltekit:generated>/env/public/client.js';
diff --git a/packages/kit/src/runtime/app/env/public/server.js b/packages/kit/src/runtime/app/env/public/server.js
index 955eca9e2ede..a1a3d5c2576a 100644
--- a/packages/kit/src/runtime/app/env/public/server.js
+++ b/packages/kit/src/runtime/app/env/public/server.js
@@ -1 +1 @@
-export * from '__sveltekit/env/public/server';
+export * from '<sveltekit:generated>/env/public/server.js';
diff --git a/packages/kit/src/runtime/server/env_module.js b/packages/kit/src/runtime/server/env_module.js
index dd61ba3a9b7e..e18aaae5dd1f 100644
--- a/packages/kit/src/runtime/server/env_module.js
+++ b/packages/kit/src/runtime/server/env_module.js
@@ -1,5 +1,5 @@
 import * as devalue from 'devalue';
-import { rendered_env } from '__sveltekit/env';
+import { rendered_env } from '<sveltekit:generated>/env/config.js';
 
 /** @type {string} */
 let payload;
diff --git a/packages/kit/src/runtime/server/index.js b/packages/kit/src/runtime/server/index.js
index 9f02fb6788f6..86112c9bfe61 100644
--- a/packages/kit/src/runtime/server/index.js
+++ b/packages/kit/src/runtime/server/index.js
@@ -4,7 +4,7 @@ import { respond } from './respond.js';
 import { create_request_state } from './state.js';
 import { options, get_hooks } from '__SERVER__/internal.js';
 import { set_read_implementation, set_manifest, fix_stack_trace } from './internal.js';
-import { set_env } from '__sveltekit/env';
+import { set_env } from '<sveltekit:generated>/env/config.js';
 import { init_tracing } from '@sveltejs/kit/internal/server';
 import { DEV } from 'esm-env';
 import { init_transport } from '#app/internal/transport';
diff --git a/packages/kit/src/runtime/server/page/render.js b/packages/kit/src/runtime/server/page/render.js
index ca69ef91aa68..b4d131e4d7bd 100644
--- a/packages/kit/src/runtime/server/page/render.js
+++ b/packages/kit/src/runtime/server/page/render.js
@@ -21,7 +21,7 @@ import { try_get_request_store, with_request_store } from '@sveltejs/kit/interna
 import { text_encoder } from '../../utils.js';
 import { count_non_ssi_comments, get_global_name } from '../utils.js';
 import { handle_error_and_jsonify } from '../errors.js';
-import * as env from '__sveltekit/env';
+import * as env from '<sveltekit:generated>/env/config.js';
 import { collect_remote_data } from '../remote-functions.js';
 import Root from '../../components/root.svelte';
 import { render } from 'svelte/server';
diff --git a/packages/kit/src/types/ambient-private.d.ts b/packages/kit/src/types/ambient-private.d.ts
index 3ddf07b9cdcb..6978843a1f7c 100644
--- a/packages/kit/src/types/ambient-private.d.ts
+++ b/packages/kit/src/types/ambient-private.d.ts
@@ -21,7 +21,7 @@ declare module '__sveltekit/server' {
 	export function set_read_implementation(fn: (path: string) => ReadableStream): void;
 }
 
-declare module '__sveltekit/env' {
+declare module '<sveltekit:generated>/env/config.js' {
 	// exported environment variables are defined in env.d.ts
 
 	/** Populate exported environment variables */
@@ -34,15 +34,15 @@ declare module '__sveltekit/env' {
 	export const rendered_env: Record<string, any>;
 }
 
-declare module '__sveltekit/env/private' {
+declare module '<sveltekit:generated>/env/private/server.js' {
 	// exported environment variables are defined in env.d.ts
 }
 
-declare module '__sveltekit/env/public/client' {
+declare module '<sveltekit:generated>/env/public/client.js' {
 	// exported environment variables are defined in env.d.ts
 }
 
-declare module '__sveltekit/env/public/server' {
+declare module '<sveltekit:generated>/env/public/server.js' {
 	// exported environment variables are defined in env.d.ts
 }