diff --git a/apps/partner-sas/app/ClientComponent.tsx b/apps/partner-sas/app/[lang]/ClientComponent.tsx
similarity index 100%
rename from apps/partner-sas/app/ClientComponent.tsx
rename to apps/partner-sas/app/[lang]/ClientComponent.tsx
diff --git a/apps/partner-sas/app/layout.tsx b/apps/partner-sas/app/[lang]/layout.tsx
similarity index 85%
rename from apps/partner-sas/app/layout.tsx
rename to apps/partner-sas/app/[lang]/layout.tsx
index 7919902db..cc501de95 100644
--- a/apps/partner-sas/app/layout.tsx
+++ b/apps/partner-sas/app/[lang]/layout.tsx
@@ -1,14 +1,13 @@
 import "@scandic-hotels/design-system/style.css"
 import "@scandic-hotels/design-system/fonts.css"
 import "@/public/_static/css/design-system-new-deprecated.css"
-import "./globals.css"
 
 import { Lang } from "@scandic-hotels/common/constants/language"
 import { TrpcProvider } from "@scandic-hotels/trpc/Provider"
 
-import { getMessages } from "../i18n"
-import ClientIntlProvider from "../i18n/Provider"
-import { setLang } from "../i18n/serverContext"
+import { getMessages } from "@/i18n"
+import ClientIntlProvider from "@/i18n/Provider"
+import { setLang } from "@/i18n/serverContext"
 
 import type { Metadata } from "next"
 
@@ -27,8 +26,7 @@ type RootLayoutProps = {
 }
 
 export default async function RootLayout(props: RootLayoutProps) {
-  // const params = await props.params
-  const params = { lang: Lang.sv }
+  const params = await props.params
 
   const { children } = props
 
diff --git a/apps/partner-sas/app/[lang]/middleware-error/404/page.tsx b/apps/partner-sas/app/[lang]/middleware-error/404/page.tsx
new file mode 100644
index 000000000..d61fa34cb
--- /dev/null
+++ b/apps/partner-sas/app/[lang]/middleware-error/404/page.tsx
@@ -0,0 +1,4 @@
+export default function NotFoundPage() {
+  // eslint-disable-next-line formatjs/no-literal-string-in-jsx
+  return <div>Not found, forgot lang in url?</div>
+}
diff --git a/apps/partner-sas/app/[lang]/middleware-error/[status]/page.module.css b/apps/partner-sas/app/[lang]/middleware-error/[status]/page.module.css
new file mode 100644
index 000000000..7f039aed6
--- /dev/null
+++ b/apps/partner-sas/app/[lang]/middleware-error/[status]/page.module.css
@@ -0,0 +1,3 @@
+.layout {
+  font-family: var(--typography-Body-Regular-fontFamily);
+}
diff --git a/apps/partner-sas/app/[lang]/middleware-error/[status]/page.tsx b/apps/partner-sas/app/[lang]/middleware-error/[status]/page.tsx
new file mode 100644
index 000000000..13ff1aa2e
--- /dev/null
+++ b/apps/partner-sas/app/[lang]/middleware-error/[status]/page.tsx
@@ -0,0 +1,16 @@
+import styles from "./page.module.css"
+
+import type { Lang } from "@scandic-hotels/common/constants/language"
+
+export default async function MiddlewareError(props: {
+  params: Promise<{ lang: Lang; status: string }>
+}) {
+  const params = await props.params
+
+  return (
+    // eslint-disable-next-line formatjs/no-literal-string-in-jsx
+    <div className={styles.layout}>
+      Middleware error {params.lang} {params.status}
+    </div>
+  )
+}
diff --git a/apps/partner-sas/app/[lang]/not-found.tsx b/apps/partner-sas/app/[lang]/not-found.tsx
new file mode 100644
index 000000000..bca1006c4
--- /dev/null
+++ b/apps/partner-sas/app/[lang]/not-found.tsx
@@ -0,0 +1,4 @@
+export default function NotFoundPage() {
+  // eslint-disable-next-line formatjs/no-literal-string-in-jsx
+  return <div>Not Found, missing lang in url?</div>
+}
diff --git a/apps/partner-sas/app/page.module.css b/apps/partner-sas/app/[lang]/page.module.css
similarity index 100%
rename from apps/partner-sas/app/page.module.css
rename to apps/partner-sas/app/[lang]/page.module.css
diff --git a/apps/partner-sas/app/page.tsx b/apps/partner-sas/app/[lang]/page.tsx
similarity index 97%
rename from apps/partner-sas/app/page.tsx
rename to apps/partner-sas/app/[lang]/page.tsx
index 9b0be0a54..be56c55ef 100644
--- a/apps/partner-sas/app/page.tsx
+++ b/apps/partner-sas/app/[lang]/page.tsx
@@ -4,7 +4,8 @@ import { Typography } from "@scandic-hotels/design-system/Typography"
 
 import { serverClient } from "@/lib/trpc"
 
-import { getIntl } from "../i18n"
+import { getIntl } from "@/i18n"
+
 import { ClientComponent } from "./ClientComponent"
 
 import styles from "./page.module.css"
diff --git a/apps/partner-sas/app/globals.css b/apps/partner-sas/app/globals.css
deleted file mode 100644
index 25fa51c5a..000000000
--- a/apps/partner-sas/app/globals.css
+++ /dev/null
@@ -1,2 +0,0 @@
-body {
-}
diff --git a/apps/partner-sas/env/server.ts b/apps/partner-sas/env/server.ts
new file mode 100644
index 000000000..032203dff
--- /dev/null
+++ b/apps/partner-sas/env/server.ts
@@ -0,0 +1,18 @@
+import { createEnv } from "@t3-oss/env-nextjs"
+import { z } from "zod"
+
+export const env = createEnv({
+  /**
+   * Due to t3-env only checking typeof window === "undefined"
+   * and Netlify running Deno, window is never "undefined"
+   * https://github.com/t3-oss/t3-env/issues/154
+   */
+  isServer: typeof window === "undefined" || "Deno" in window,
+  server: {
+    PUBLIC_URL: z.string().default(""),
+  },
+  emptyStringAsUndefined: true,
+  runtimeEnv: {
+    PUBLIC_URL: process.env.NEXT_PUBLIC_PUBLIC_URL,
+  },
+})
diff --git a/apps/partner-sas/middleware.ts b/apps/partner-sas/middleware.ts
new file mode 100644
index 000000000..785855436
--- /dev/null
+++ b/apps/partner-sas/middleware.ts
@@ -0,0 +1,113 @@
+import * as Sentry from "@sentry/nextjs"
+import { type NextMiddleware, NextResponse } from "next/server"
+
+import { Lang } from "@scandic-hotels/common/constants/language"
+import { logger } from "@scandic-hotels/common/logger"
+import { findLang } from "@scandic-hotels/common/utils/languages"
+
+import * as invalidUrl from "@/middlewares/invalidUrl"
+import * as trailingSlash from "@/middlewares/trailingSlash"
+import { getDefaultRequestHeaders } from "@/middlewares/utils"
+
+export const middleware: NextMiddleware = async (request, event) => {
+  // auth() overrides the request origin, we need the original for internal rewrites
+  // @see getInternalNextURL()
+  request.headers.set("x-sh-origin", request.nextUrl.origin)
+
+  const headers = getDefaultRequestHeaders(request)
+  const lang = findLang(request.nextUrl.pathname)
+
+  if (!lang) {
+    // Lang is required for all our middleware.
+    // Without it we shortcircuit early.
+
+    // Default to English if no lang is found.
+    headers.set("x-lang", Lang.en)
+    return NextResponse.rewrite(
+      new URL(`/${Lang.en}/middleware-error/404`, request.nextUrl),
+      {
+        request: {
+          headers,
+        },
+        status: 404,
+        statusText: "Not found",
+      }
+    )
+  }
+
+  // Note that the order of middlewares is important since that is the order they are matched by.
+  const middlewares: { middleware: NextMiddleware; matcher: any }[] = [
+    invalidUrl,
+    trailingSlash,
+    // authRequired,
+    // handleAuth,
+    // bookingFlow,
+    // cmsContent,
+  ]
+
+  try {
+    for (let i = 0; i < middlewares.length; ++i) {
+      const middleware = middlewares[i]
+
+      if (middleware.matcher(request)) {
+        const result = await middleware.middleware(request, event)
+
+        const _continue = result?.headers.get("x-continue")
+        if (_continue) {
+          continue
+        }
+        // Clean up internal headers
+        result?.headers.delete("x-sh-origin")
+
+        return result
+      }
+    }
+  } catch (e) {
+    if (e instanceof NextResponse && e.status) {
+      const cause = await e.json()
+      logger.error(`NextResponse Error in middleware`, cause)
+      Sentry.captureException(cause)
+
+      return NextResponse.rewrite(
+        new URL(`/${lang}/middleware-error/${e.status}`, request.nextUrl),
+        {
+          request: {
+            headers,
+          },
+          status: e.status,
+          statusText: e.statusText,
+        }
+      )
+    }
+
+    logger.error(`Error in middleware`, e)
+    Sentry.captureException(e)
+
+    return NextResponse.rewrite(
+      new URL(`/${lang}/middleware-error/500`, request.nextUrl),
+      {
+        request: {
+          headers,
+        },
+        status: 500,
+        statusText: "Internal Server Error",
+      }
+    )
+  }
+
+  // Follow through with normal App router rules.
+  return NextResponse.next({
+    request: {
+      headers,
+    },
+  })
+}
+
+export const config = {
+  /**
+   *  Copied from Clerk to protect all routes by default and handle
+   *  public routes inside middleware.
+   *  (https://clerk.com/docs/quickstarts/nextjs?utm_source=sponsorship&utm_medium=youtube&utm_campaign=code-with-antonio&utm_content=12-31-2023#add-authentication-to-your-app)
+   */
+  matcher: ["/((?!.+\\.[\\w]+$|_next|_static|.netlify|api|trpc|sitemap).*)"],
+}
diff --git a/apps/partner-sas/middlewares/invalidUrl.ts b/apps/partner-sas/middlewares/invalidUrl.ts
new file mode 100644
index 000000000..f1351bade
--- /dev/null
+++ b/apps/partner-sas/middlewares/invalidUrl.ts
@@ -0,0 +1,16 @@
+import { type NextMiddleware, NextResponse } from "next/server"
+
+import { getDefaultRequestHeaders } from "./utils"
+
+import type { MiddlewareMatcher } from "./types"
+
+export const middleware: NextMiddleware = async (request) => {
+  const headers = getDefaultRequestHeaders(request)
+  return NextResponse.next({
+    headers,
+  })
+}
+
+export const matcher: MiddlewareMatcher = (request) => {
+  return request.nextUrl.pathname.includes("*")
+}
diff --git a/apps/partner-sas/middlewares/trailingSlash.ts b/apps/partner-sas/middlewares/trailingSlash.ts
new file mode 100644
index 000000000..a4ca2fc22
--- /dev/null
+++ b/apps/partner-sas/middlewares/trailingSlash.ts
@@ -0,0 +1,25 @@
+import { type NextMiddleware, NextResponse } from "next/server"
+
+import { getPublicNextURL } from "@/server/utils"
+
+import { getDefaultRequestHeaders } from "./utils"
+
+import type { MiddlewareMatcher } from "./types"
+
+export const middleware: NextMiddleware = async (request) => {
+  const headers = getDefaultRequestHeaders(request)
+
+  const newUrl = new URL(
+    request.nextUrl.pathname.slice(0, -1),
+    getPublicNextURL(request)
+  )
+
+  return NextResponse.redirect(newUrl, {
+    headers,
+    status: 308,
+  })
+}
+
+export const matcher: MiddlewareMatcher = (request) => {
+  return request.nextUrl.pathname.endsWith("/")
+}
diff --git a/apps/partner-sas/middlewares/types.ts b/apps/partner-sas/middlewares/types.ts
new file mode 100644
index 000000000..ac9e53699
--- /dev/null
+++ b/apps/partner-sas/middlewares/types.ts
@@ -0,0 +1,3 @@
+import type { NextRequest } from "next/server"
+
+export type MiddlewareMatcher = (request: NextRequest) => boolean
diff --git a/apps/partner-sas/middlewares/utils.ts b/apps/partner-sas/middlewares/utils.ts
new file mode 100644
index 000000000..5f48598f7
--- /dev/null
+++ b/apps/partner-sas/middlewares/utils.ts
@@ -0,0 +1,22 @@
+import { findLang } from "@scandic-hotels/common/utils/languages"
+import { removeTrailingSlash } from "@scandic-hotels/common/utils/url"
+
+import { getPublicNextURL } from "@/server/utils"
+
+import type { NextRequest } from "next/server"
+
+export function getDefaultRequestHeaders(request: NextRequest) {
+  const lang = findLang(request.nextUrl.pathname)!
+  const nextUrlPublic = getPublicNextURL(request)
+  const headers = new Headers(request.headers)
+  headers.set("x-lang", lang)
+  headers.set(
+    "x-pathname",
+    removeTrailingSlash(
+      request.nextUrl.pathname.replace(`/${lang}`, "").replace(`/webview`, "")
+    )
+  )
+  headers.set("x-url", removeTrailingSlash(nextUrlPublic.href))
+
+  return headers
+}
diff --git a/apps/partner-sas/server/utils.ts b/apps/partner-sas/server/utils.ts
new file mode 100644
index 000000000..c1ceac4e3
--- /dev/null
+++ b/apps/partner-sas/server/utils.ts
@@ -0,0 +1,94 @@
+import { NextRequest } from "next/server"
+
+import { logger } from "@scandic-hotels/common/logger"
+
+import { env } from "@/env/server"
+/**
+ * Use this function when you want to create URLs that are public facing, for
+ * example for redirects or redirectTo query parameters.
+ * Dedicated environments are behind Akamai (test, stage, production). They have
+ * env.PUBLIC_URL set.
+ * All other environment like deploy previews and branch deployments are not
+ * behind Akamai and therefore do not have env.PUBLIC_URL set.
+ * We need this approach because Netlify uses x-forwarded-host internally and
+ * strips it from ever reaching our code.
+ * TODO: Replace this approach with custom header in Akamai that mirrors the
+ * value in x-forwarded-host which would not get stripped by Netlify.
+ * @param request The incoming request.
+ * @returns NextURL The public facing URL instance for the given request.
+ */
+export function getPublicNextURL(request: NextRequest) {
+  if (env.PUBLIC_URL) {
+    const publicNextURL = request.nextUrl.clone()
+    // Akamai in front of Netlify for dedicated environments
+    // require us to rewrite the incoming host and hostname
+    // to match the public URL used to visit Akamai.
+    const url = new URL(env.PUBLIC_URL)
+    publicNextURL.host = url.host
+    publicNextURL.hostname = url.hostname
+    return publicNextURL
+  }
+  return request.nextUrl
+}
+
+/**
+ * Use this function when you want the public facing URL for the given request.
+ * Read about the motivation in getPublicNextURL above.
+ * @see getPublicNextURL
+ * @param request The incoming request.
+ * @returns string The public facing origin for the given request.
+ */
+export function getPublicURL(request: NextRequest) {
+  if (env.PUBLIC_URL) {
+    return env.PUBLIC_URL
+  }
+  return request.nextUrl.origin
+}
+
+/**
+ * Use this function when you want to create URLs that are internal (behind Akamai),
+ * for example for rewrites. Mainly used for middleware wrapped in auth().
+ * The auth() function overrides the origin of the incoming request. It sets it
+ * to the origin of AUTH_URL/NEXTAUTH_URL. This means we cannot use the augmented
+ * request from auth() for rewrites, as those will point to auth url origin
+ * (in front of Akamai) and not the origin of the incoming request (behind Akamai).
+ * This results in rewrites going over the internet instead of going through the
+ * internal routing at Netlify.
+ * For dedicated environments (test, stage and production) we are behind Akamai.
+ * For those we have set a value for AUTH_URL/NEXTAUTH_URL, they point to the
+ * PUBLIC_URL. For rewrites we need the internal origin inside Netlify.
+ * In middleware.ts we copy the incoming origin to a header 'x-sh-origin'. We try
+ * and use that first, if not present we assume the internal origin is the value
+ * of the host header, as that is what Netlify used for routing to this deployment.
+ * @param request The incoming request.
+ * @returns NextURL The internal request, in Netlify behind Akamai.
+ */
+export function getInternalNextURL(request: NextRequest) {
+  const { href, origin } = request.nextUrl
+
+  const originHeader = request.headers.get("x-sh-origin")
+  if (originHeader) {
+    logger.debug(`[internalNextUrl] using x-sh-origin header`, {
+      origin,
+      originHeader,
+      newOrigin: href.replace(origin, originHeader),
+    })
+    return new NextRequest(href.replace(origin, originHeader), request).nextUrl
+  }
+
+  const hostHeader = request.headers.get("host")
+  if (hostHeader) {
+    const inputHostOrigin = `${request.nextUrl.protocol}//${hostHeader}`
+    logger.debug(`[internalNextUrl] using host header`, {
+      origin,
+      hostHeader,
+      hostOrigin: inputHostOrigin,
+      newOrigin: href.replace(origin, inputHostOrigin),
+    })
+    const { origin: hostOrigin } = new URL(inputHostOrigin)
+    return new NextRequest(href.replace(origin, hostOrigin), request).nextUrl
+  }
+
+  logger.debug(`[internalNextUrl] falling back to incoming request`)
+  return request.nextUrl
+}