diff --git a/apps/web/app/(auth)/login/new/page.tsx b/apps/web/app/(auth)/login/new/page.tsx
index 82d0fd48..6272cd96 100644
--- a/apps/web/app/(auth)/login/new/page.tsx
+++ b/apps/web/app/(auth)/login/new/page.tsx
@@ -17,6 +17,7 @@ import { motion } from "motion/react"
 import { dmSansClassName } from "@/lib/fonts"
 import { cn } from "@lib/utils"
 import { Logo } from "@ui/assets/Logo"
+import { resolveAuthRedirectUrl } from "@/lib/url-helpers"
 
 function isMcpOAuthAuthorizeContext(sp: Pick<URLSearchParams, "get">): boolean {
 	return sp.get("response_type") === "code" && Boolean(sp.get("client_id"))
@@ -113,9 +114,25 @@ export default function LoginPage() {
 		if (sessionPending) return
 		if (!sessionData?.session) return
 		const sp = new URLSearchParams(oauthQueryForResume)
-		if (!isMcpOAuthAuthorizeContext(sp)) return
-		window.location.assign(buildMcpAuthorizeResumeUrl(sp))
-	}, [sessionPending, sessionData?.session, oauthQueryForResume])
+		if (isMcpOAuthAuthorizeContext(sp)) {
+			window.location.assign(buildMcpAuthorizeResumeUrl(sp))
+			return
+		}
+		const redirectUrl = params.get("redirect")
+		if (redirectUrl) {
+			window.location.assign(
+				resolveAuthRedirectUrl(redirectUrl, window.location.origin).toString(),
+			)
+			return
+		}
+		router.replace("/")
+	}, [
+		sessionPending,
+		sessionData?.session,
+		oauthQueryForResume,
+		params,
+		router,
+	])
 
 	// Get redirect URL from query params
 	const redirectUrl = params.get("redirect")
@@ -128,17 +145,7 @@ export default function LoginPage() {
 			return buildMcpAuthorizeResumeUrl(params)
 		}
 
-		let finalUrl: URL
-
-		if (redirectUrl) {
-			try {
-				finalUrl = new URL(redirectUrl, origin)
-			} catch {
-				finalUrl = new URL(origin)
-			}
-		} else {
-			finalUrl = new URL(origin)
-		}
+		const finalUrl = resolveAuthRedirectUrl(redirectUrl, origin)
 
 		finalUrl.searchParams.set("extension-auth-success", "true")
 		return finalUrl.toString()
diff --git a/apps/web/lib/url-helpers.ts b/apps/web/lib/url-helpers.ts
index 832b8722..cfd57209 100644
--- a/apps/web/lib/url-helpers.ts
+++ b/apps/web/lib/url-helpers.ts
@@ -1,3 +1,47 @@
+const PROXY_LOCAL_HOSTS = new Set(["localhost", "127.0.0.1", "::1"])
+
+/** Reconstruct the browser-facing URL when running behind portless (or similar). */
+export function getPublicRequestUrl(request: Request): URL {
+	const internal = new URL(request.url)
+	const forwardedHost = request.headers
+		.get("x-forwarded-host")
+		?.split(",")[0]
+		?.trim()
+	if (forwardedHost) {
+		const proto = request.headers.get("x-forwarded-proto") || "https"
+		return new URL(
+			`${proto}://${forwardedHost}${internal.pathname}${internal.search}`,
+		)
+	}
+	const portlessUrl = process.env.PORTLESS_URL
+	if (portlessUrl) {
+		try {
+			const base = new URL(portlessUrl)
+			return new URL(`${base.origin}${internal.pathname}${internal.search}`)
+		} catch {}
+	}
+	return internal
+}
+
+/** Map portless proxy localhost redirects back to the current public origin. */
+export function resolveAuthRedirectUrl(
+	redirectUrl: string | null,
+	origin: string,
+): URL {
+	const fallback = new URL(origin)
+	if (!redirectUrl) return fallback
+	try {
+		const target = new URL(redirectUrl)
+		if (PROXY_LOCAL_HOSTS.has(target.hostname)) {
+			return new URL(`${target.pathname}${target.search}`, origin)
+		}
+		if (target.origin === origin) return target
+		return fallback
+	} catch {
+		return fallback
+	}
+}
+
 /**
  * Validates if a string is a valid URL.
  */
diff --git a/apps/web/middleware.ts b/apps/web/middleware.ts
index 0473e315..4715c571 100644
--- a/apps/web/middleware.ts
+++ b/apps/web/middleware.ts
@@ -1,14 +1,22 @@
 import { getSessionCookie } from "better-auth/cookies"
 import { NextResponse } from "next/server"
+import { getPublicRequestUrl } from "@/lib/url-helpers"
+
+function getAuthSessionCookie(request: Request): string | null {
+	return (
+		getSessionCookie(request) ??
+		getSessionCookie(request, { cookiePrefix: "better-auth-dev" })
+	)
+}
 
 export default async function proxy(request: Request) {
 	console.debug("[PROXY] === PROXY START ===")
-	const url = new URL(request.url)
+	const url = getPublicRequestUrl(request)
 
 	console.debug("[PROXY] Path:", url.pathname)
 	console.debug("[PROXY] Method:", request.method)
 
-	const sessionCookie = getSessionCookie(request)
+	const sessionCookie = getAuthSessionCookie(request)
 	console.debug("[PROXY] Session cookie exists:", !!sessionCookie)
 
 	// Always allow access to login and waitlist pages
@@ -40,9 +48,9 @@ export default async function proxy(request: Request) {
 		console.debug(
 			"[PROXY] No session cookie and not on public path, redirecting to /login",
 		)
-		const url = new URL("/login", request.url)
-		url.searchParams.set("redirect", request.url)
-		return NextResponse.redirect(url)
+		const loginUrl = new URL("/login", url.origin)
+		loginUrl.searchParams.set("redirect", url.toString())
+		return NextResponse.redirect(loginUrl)
 	}
 
 	// TEMPORARILY DISABLED: Waitlist check