diff --git a/apps/web/middleware.test.ts b/apps/web/middleware.test.ts
new file mode 100644
index 000000000..65e310e1c
--- /dev/null
+++ b/apps/web/middleware.test.ts
@@ -0,0 +1,95 @@
+import { beforeEach, describe, expect, it, mock } from "bun:test"
+
+const getSession = mock()
+
+mock.module("@lib/auth.middleware", () => ({
+	middlewareAuthClient: { getSession },
+}))
+
+const { default: proxy } = await import("./middleware")
+
+beforeEach(() => {
+	getSession.mockReset()
+})
+
+describe("auth proxy", () => {
+	it("rejects API requests with a forged session cookie", async () => {
+		getSession.mockResolvedValue(null)
+
+		const response = await proxy(
+			new Request("https://app.supermemory.ai/api/onboarding/research", {
+				headers: {
+					cookie: "better-auth.session_token=forged",
+				},
+			}),
+		)
+
+		expect(response.status).toBe(401)
+		expect(await response.json()).toEqual({ error: "Unauthorized" })
+		expect(getSession).toHaveBeenCalledWith({
+			fetchOptions: {
+				headers: {
+					cookie: "better-auth.session_token=forged",
+				},
+			},
+		})
+	})
+
+	it("does not validate API requests without a session cookie", async () => {
+		const response = await proxy(
+			new Request("https://app.supermemory.ai/api/onboarding/research"),
+		)
+
+		expect(response.status).toBe(401)
+		expect(getSession).not.toHaveBeenCalled()
+	})
+
+	it("redirects page requests with an expired session cookie", async () => {
+		getSession.mockResolvedValue(null)
+
+		const response = await proxy(
+			new Request("https://app.supermemory.ai/settings", {
+				headers: {
+					cookie: "better-auth.session_token=expired",
+				},
+			}),
+		)
+
+		expect(response.status).toBe(307)
+		expect(response.headers.get("location")).toBe(
+			"https://app.supermemory.ai/login?redirect=https%3A%2F%2Fapp.supermemory.ai%2Fsettings",
+		)
+	})
+
+	it("allows API requests with a valid session", async () => {
+		getSession.mockResolvedValue({
+			session: {},
+			user: {},
+		})
+
+		const response = await proxy(
+			new Request("https://app.supermemory.ai/api/onboarding/research", {
+				headers: {
+					cookie: "better-auth.session_token=valid",
+				},
+			}),
+		)
+
+		expect(response.status).toBe(200)
+		expect(response.headers.get("x-middleware-next")).toBe("1")
+	})
+
+	it("fails closed when session validation is unavailable", async () => {
+		getSession.mockRejectedValue(new Error("backend unavailable"))
+
+		const response = await proxy(
+			new Request("https://app.supermemory.ai/api/onboarding/research", {
+				headers: {
+					cookie: "better-auth.session_token=unknown",
+				},
+			}),
+		)
+
+		expect(response.status).toBe(401)
+	})
+})
diff --git a/apps/web/middleware.ts b/apps/web/middleware.ts
index ea7b1ec1c..284a46b93 100644
--- a/apps/web/middleware.ts
+++ b/apps/web/middleware.ts
@@ -1,5 +1,6 @@
 import { getSessionCookie } from "better-auth/cookies"
 import { NextResponse } from "next/server"
+import { middlewareAuthClient } from "@lib/auth.middleware"
 import { getPublicRequestUrl } from "@/lib/url-helpers"
 
 const LOCAL_DEV_HOSTS = new Set(["localhost", "127.0.0.1", "::1"])
@@ -11,6 +12,22 @@ function getAuthSessionCookie(request: Request): string | null {
 	)
 }
 
+async function hasValidSession(request: Request): Promise<boolean> {
+	try {
+		const session = await middlewareAuthClient.getSession({
+			fetchOptions: {
+				headers: {
+					cookie: request.headers.get("cookie") ?? "",
+				},
+			},
+		})
+		return Boolean(session?.session && session.user)
+	} catch (error) {
+		console.error("[PROXY] Failed to validate session", error)
+		return false
+	}
+}
+
 export default async function proxy(request: Request) {
 	console.debug("[PROXY] === PROXY START ===")
 	const url = getPublicRequestUrl(request)
@@ -58,22 +75,26 @@ export default async function proxy(request: Request) {
 		return NextResponse.next()
 	}
 
+	const validSession = sessionCookie ? await hasValidSession(request) : false
+
 	if (url.pathname.startsWith("/api/")) {
-		if (!sessionCookie) {
-			console.debug("[MIDDLEWARE] API route without session, returning 401")
+		if (!validSession) {
+			console.debug(
+				"[MIDDLEWARE] API route without valid session, returning 401",
+			)
 			return new Response(JSON.stringify({ error: "Unauthorized" }), {
 				status: 401,
 				headers: { "Content-Type": "application/json" },
 			})
 		}
-		console.debug("[MIDDLEWARE] API route with session, allowing access")
+		console.debug("[MIDDLEWARE] API route with valid session, allowing access")
 		return NextResponse.next()
 	}
 
-	// If no session cookie and not on a public path, redirect to login
-	if (!sessionCookie) {
+	// If no valid session and not on a public path, redirect to login
+	if (!validSession) {
 		console.debug(
-			"[PROXY] No session cookie and not on public path, redirecting to /login",
+			"[PROXY] No valid session and not on public path, redirecting to /login",
 		)
 		const loginUrl = new URL("/login", url.origin)
 		loginUrl.searchParams.set("redirect", url.toString())