diff --git a/changelog.d/fixes/10329-zai-web-auth-semantics.md b/changelog.d/fixes/10329-zai-web-auth-semantics.md
new file mode 100644
index 0000000000..c4e6703112
--- /dev/null
+++ b/changelog.d/fixes/10329-zai-web-auth-semantics.md
@@ -0,0 +1 @@
+- **fix(providers):** validate Z.ai web Local Storage sessions against the authenticated user-settings endpoint and preserve exact upstream status codes ([#10329](https://github.com/diegosouzapw/OmniRoute/pull/10329)) — thanks @Zartharas
diff --git a/src/lib/providers/validation.ts b/src/lib/providers/validation.ts
index 2d05ece895..5efff93cb9 100644
--- a/src/lib/providers/validation.ts
+++ b/src/lib/providers/validation.ts
@@ -81,6 +81,7 @@ import {
   validatePoeProvider,
 } from "./validation/audioMiscProviders";
 import { validateChatGptWebCodexProvider } from "./validation/chatgptWebCodex";
+import { validateZaiWebProvider } from "./validation/zaiWeb";
 import { validateSearchProvider, SEARCH_VALIDATOR_CONFIGS } from "./validation/searchProviders";
 import {
   validateClarifaiProvider,
@@ -227,7 +228,7 @@ export async function validateProviderApiKey({ provider, apiKey, providerSpecifi
           error:
             "Modal requires a Base URL pointing to your OpenAI-compatible Modal app " +
             "(e.g. https://<workspace>--<app>.modal.run/v1). " +
-            "Fill in the \"Base URL override\" field.",
+            'Fill in the "Base URL override" field.',
         };
       }
       return validateOpenAILikeProvider({
@@ -249,6 +250,7 @@ export async function validateProviderApiKey({ provider, apiKey, providerSpecifi
     snowflake: validateSnowflakeProvider,
     gigachat: validateGigachatProvider,
     "deepseek-web": validateDeepSeekWebProvider,
+    "zai-web": validateZaiWebProvider,
     "grok-web": validateGrokWebProvider,
     "qwen-web": validateQwenWebProvider,
     "kimi-web": validateKimiWebProvider,
diff --git a/src/lib/providers/validation/zaiWeb.ts b/src/lib/providers/validation/zaiWeb.ts
new file mode 100644
index 0000000000..6d151d4130
--- /dev/null
+++ b/src/lib/providers/validation/zaiWeb.ts
@@ -0,0 +1,52 @@
+import { extractZaiToken } from "@omniroute/open-sse/services/zaiWebCredentials.ts";
+import { toValidationErrorResult, validationRead } from "./transport";
+
+const ZAI_SESSION_PROBE_URL = "https://chat.z.ai/api/v1/users/user/settings";
+
+export async function validateZaiWebProvider({ apiKey }: { apiKey?: string }) {
+  const token = extractZaiToken(String(apiKey || ""));
+
+  if (!token) {
+    return {
+      valid: false,
+      error:
+        'Invalid Z.ai web-session credential — copy the "token" value from chat.z.ai Local Storage.',
+    };
+  }
+
+  try {
+    const response = await validationRead(ZAI_SESSION_PROBE_URL, {
+      method: "GET",
+      headers: {
+        Accept: "application/json, text/plain, */*",
+        Authorization: `Bearer ${token}`,
+        Origin: "https://chat.z.ai",
+        Referer: "https://chat.z.ai/",
+      },
+    });
+
+    if (response.status >= 200 && response.status < 300) {
+      return {
+        valid: true,
+        error: null,
+      };
+    }
+
+    if (response.status === 401) {
+      return {
+        valid: false,
+        error:
+          'Invalid or expired Z.ai web-session credential — copy a fresh "token" value from chat.z.ai Local Storage.',
+        statusCode: 401,
+      };
+    }
+
+    return {
+      valid: false,
+      error: `Z.ai session validation returned HTTP ${response.status}`,
+      statusCode: response.status,
+    };
+  } catch (error: unknown) {
+    return toValidationErrorResult(error);
+  }
+}
diff --git a/tests/unit/zai-web-auth-semantics.test.ts b/tests/unit/zai-web-auth-semantics.test.ts
new file mode 100644
index 0000000000..ff0561f718
--- /dev/null
+++ b/tests/unit/zai-web-auth-semantics.test.ts
@@ -0,0 +1,108 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+const originalFetch = globalThis.fetch;
+
+const { validateProviderApiKey } = await import("../../src/lib/providers/validation.ts");
+
+let nextStatus = 200;
+let lastRequest: {
+  url: string;
+  method: string;
+  authorization: string;
+  cookie: string;
+} | null = null;
+
+let lastResponse: Response | null = null;
+
+globalThis.fetch = (async (input: RequestInfo | URL, init?: RequestInit) => {
+  const headers = new Headers(init?.headers);
+
+  lastRequest = {
+    url: String(input),
+    method: String(init?.method || "GET"),
+    authorization: headers.get("authorization") || "",
+    cookie: headers.get("cookie") || "",
+  };
+
+  lastResponse = new Response(
+    JSON.stringify({
+      secret: "response-body-must-not-be-consumed",
+    }),
+    {
+      status: nextStatus,
+      headers: {
+        "content-type": "application/json",
+      },
+    }
+  );
+
+  return lastResponse;
+}) as typeof fetch;
+
+test.after(() => {
+  globalThis.fetch = originalFetch;
+});
+
+async function validate(status: number) {
+  nextStatus = status;
+  lastRequest = null;
+  lastResponse = null;
+
+  return validateProviderApiKey({
+    provider: "zai-web",
+    apiKey: "synthetic-zai-token",
+    providerSpecificData: {},
+  });
+}
+
+test("zai-web uses the token-only authenticated user-settings GET", async () => {
+  const result = await validate(200);
+
+  assert.equal(result.valid, true);
+
+  assert.equal(lastRequest?.url, "https://chat.z.ai/api/v1/users/user/settings");
+
+  assert.equal(lastRequest?.method, "GET");
+
+  assert.equal(lastRequest?.authorization, "Bearer synthetic-zai-token");
+
+  assert.equal(lastRequest?.cookie, "");
+
+  assert.equal(lastResponse?.bodyUsed, false);
+});
+
+test("zai-web preserves exact 401 as credential rejection", async () => {
+  const result = await validate(401);
+
+  assert.equal(result.valid, false);
+  assert.equal(result.statusCode, 401);
+
+  assert.match(result.error, /invalid or expired/i);
+
+  assert.equal(lastResponse?.bodyUsed, false);
+});
+
+test("zai-web preserves 403 without calling it expired", async () => {
+  const result = await validate(403);
+
+  assert.equal(result.valid, false);
+  assert.equal(result.statusCode, 403);
+
+  assert.doesNotMatch(result.error, /invalid or expired/i);
+
+  assert.equal(lastResponse?.bodyUsed, false);
+});
+
+test("zai-web preserves rate-limit and server statuses", async () => {
+  for (const status of [429, 503]) {
+    const result = await validate(status);
+
+    assert.equal(result.valid, false);
+    assert.equal(result.statusCode, status);
+
+    assert.doesNotMatch(result.error, /invalid or expired/i);
+
+    assert.equal(lastResponse?.bodyUsed, false);
+  }
+});