diff --git a/backend/src/server/lib/cookie.ts b/backend/src/server/lib/cookie.ts
new file mode 100644
index 000000000..cc6956056
--- /dev/null
+++ b/backend/src/server/lib/cookie.ts
@@ -0,0 +1,38 @@
+import { FastifyReply } from "fastify";
+
+import { getConfig } from "@app/lib/config/env";
+import { logger } from "@app/lib/logger";
+
+export function addAuthOriginDomainCookie(res: FastifyReply) {
+  try {
+    const appCfg = getConfig();
+
+    // Only set the cookie if the app is running in cloud mode
+    if (!appCfg.isCloud) return;
+
+    const siteUrl = appCfg.SITE_URL!;
+    let domain: string;
+
+    const { hostname } = new URL(siteUrl);
+
+    const parts = hostname.split(".");
+
+    if (parts.length >= 2) {
+      // For `app.infisical.com` => `.infisical.com`
+      domain = `.${parts.slice(-2).join(".")}`;
+    } else {
+      // If somehow only "example", fallback to itself
+      domain = `.${hostname}`;
+    }
+
+    void res.setCookie("aod", siteUrl, {
+      domain,
+      path: "/",
+      sameSite: "strict",
+      httpOnly: false,
+      secure: appCfg.HTTPS_ENABLED
+    });
+  } catch (error) {
+    logger.error(error, "Failed to set auth origin domain cookie");
+  }
+}
diff --git a/backend/src/server/routes/v1/admin-router.ts b/backend/src/server/routes/v1/admin-router.ts
index 2e31077a7..6cc50dc5c 100644
--- a/backend/src/server/routes/v1/admin-router.ts
+++ b/backend/src/server/routes/v1/admin-router.ts
@@ -12,6 +12,7 @@ import { getConfig, overridableKeys } from "@app/lib/config/env";
 import { crypto } from "@app/lib/crypto/cryptography";
 import { BadRequestError } from "@app/lib/errors";
 import { invalidateCacheLimit, readLimit, writeLimit } from "@app/server/config/rateLimiter";
+import { addAuthOriginDomainCookie } from "@app/server/lib/cookie";
 import { getTelemetryDistinctId } from "@app/server/lib/telemetry";
 import { verifySuperAdmin } from "@app/server/plugins/auth/superAdmin";
 import { verifyAuth } from "@app/server/plugins/auth/verify-auth";
@@ -593,6 +594,8 @@ export const registerAdminRouter = async (server: FastifyZodProvider) => {
         secure: appCfg.HTTPS_ENABLED
       });
 
+      addAuthOriginDomainCookie(res);
+
       return {
         message: "Successfully set up admin account",
         user: user.user,
diff --git a/backend/src/server/routes/v1/sso-router.ts b/backend/src/server/routes/v1/sso-router.ts
index 5e2518362..0aec39f3e 100644
--- a/backend/src/server/routes/v1/sso-router.ts
+++ b/backend/src/server/routes/v1/sso-router.ts
@@ -22,6 +22,7 @@ import { logger } from "@app/lib/logger";
 import { ms } from "@app/lib/ms";
 import { fetchGithubEmails, fetchGithubUser } from "@app/lib/requests/github";
 import { authRateLimit } from "@app/server/config/rateLimiter";
+import { addAuthOriginDomainCookie } from "@app/server/lib/cookie";
 import { AuthMethod } from "@app/services/auth/auth-type";
 import { OrgAuthMethod } from "@app/services/org/org-types";
 import { getServerCfg } from "@app/services/super-admin/super-admin-service";
@@ -475,6 +476,8 @@ export const registerSsoRouter = async (server: FastifyZodProvider) => {
         secure: appCfg.HTTPS_ENABLED
       });
 
+      addAuthOriginDomainCookie(res);
+
       return {
         encryptionVersion: data.user.encryptionVersion,
         token: data.token.access,
diff --git a/backend/src/server/routes/v2/mfa-router.ts b/backend/src/server/routes/v2/mfa-router.ts
index bdb609432..59a3943f7 100644
--- a/backend/src/server/routes/v2/mfa-router.ts
+++ b/backend/src/server/routes/v2/mfa-router.ts
@@ -4,6 +4,7 @@ import { getConfig } from "@app/lib/config/env";
 import { crypto } from "@app/lib/crypto";
 import { BadRequestError, NotFoundError } from "@app/lib/errors";
 import { mfaRateLimit } from "@app/server/config/rateLimiter";
+import { addAuthOriginDomainCookie } from "@app/server/lib/cookie";
 import { AuthModeMfaJwtTokenPayload, AuthTokenType, MfaMethod } from "@app/services/auth/auth-type";
 
 export const registerMfaRouter = async (server: FastifyZodProvider) => {
@@ -131,6 +132,8 @@ export const registerMfaRouter = async (server: FastifyZodProvider) => {
         secure: appCfg.HTTPS_ENABLED
       });
 
+      addAuthOriginDomainCookie(res);
+
       return {
         ...user,
         token: token.access,
diff --git a/backend/src/server/routes/v2/organization-router.ts b/backend/src/server/routes/v2/organization-router.ts
index fd60316db..c17200a30 100644
--- a/backend/src/server/routes/v2/organization-router.ts
+++ b/backend/src/server/routes/v2/organization-router.ts
@@ -10,6 +10,7 @@ import {
 import { ApiDocsTags, ORGANIZATIONS } from "@app/lib/api-docs";
 import { getConfig } from "@app/lib/config/env";
 import { readLimit, writeLimit } from "@app/server/config/rateLimiter";
+import { addAuthOriginDomainCookie } from "@app/server/lib/cookie";
 import { GenericResourceNameSchema } from "@app/server/lib/schemas";
 import { verifyAuth } from "@app/server/plugins/auth/verify-auth";
 import { ActorType, AuthMode } from "@app/services/auth/auth-type";
@@ -396,6 +397,8 @@ export const registerOrgRouter = async (server: FastifyZodProvider) => {
         secure: cfg.HTTPS_ENABLED
       });
 
+      addAuthOriginDomainCookie(res);
+
       return { organization, accessToken: tokens.accessToken };
     }
   });
diff --git a/backend/src/server/routes/v3/login-router.ts b/backend/src/server/routes/v3/login-router.ts
index 91df68e16..3a8510f34 100644
--- a/backend/src/server/routes/v3/login-router.ts
+++ b/backend/src/server/routes/v3/login-router.ts
@@ -3,6 +3,7 @@ import { z } from "zod";
 import { INFISICAL_PROVIDER_GITHUB_ACCESS_TOKEN } from "@app/lib/config/const";
 import { getConfig } from "@app/lib/config/env";
 import { authRateLimit } from "@app/server/config/rateLimiter";
+import { addAuthOriginDomainCookie } from "@app/server/lib/cookie";
 
 export const registerLoginRouter = async (server: FastifyZodProvider) => {
   server.route({
@@ -93,6 +94,8 @@ export const registerLoginRouter = async (server: FastifyZodProvider) => {
         secure: cfg.HTTPS_ENABLED
       });
 
+      addAuthOriginDomainCookie(res);
+
       void res.cookie("infisical-project-assume-privileges", "", {
         httpOnly: true,
         path: "/",
@@ -155,6 +158,8 @@ export const registerLoginRouter = async (server: FastifyZodProvider) => {
         secure: appCfg.HTTPS_ENABLED
       });
 
+      addAuthOriginDomainCookie(res);
+
       void res.cookie("infisical-project-assume-privileges", "", {
         httpOnly: true,
         path: "/",
diff --git a/backend/src/server/routes/v3/signup-router.ts b/backend/src/server/routes/v3/signup-router.ts
index 393b598cf..391c459a2 100644
--- a/backend/src/server/routes/v3/signup-router.ts
+++ b/backend/src/server/routes/v3/signup-router.ts
@@ -4,6 +4,7 @@ import { UsersSchema } from "@app/db/schemas";
 import { getConfig } from "@app/lib/config/env";
 import { ForbiddenRequestError } from "@app/lib/errors";
 import { authRateLimit, smtpRateLimit } from "@app/server/config/rateLimiter";
+import { addAuthOriginDomainCookie } from "@app/server/lib/cookie";
 import { GenericResourceNameSchema } from "@app/server/lib/schemas";
 import { getServerCfg } from "@app/services/super-admin/super-admin-service";
 import { PostHogEventTypes } from "@app/services/telemetry/telemetry-types";
@@ -170,6 +171,8 @@ export const registerSignupRouter = async (server: FastifyZodProvider) => {
         secure: appCfg.HTTPS_ENABLED
       });
 
+      addAuthOriginDomainCookie(res);
+
       return { message: "Successfully set up account", user, token: accessToken, organizationId };
     }
   });
@@ -239,6 +242,8 @@ export const registerSignupRouter = async (server: FastifyZodProvider) => {
       });
       // TODO(akhilmhdh-pg): add telemetry service
 
+      addAuthOriginDomainCookie(res);
+
       return { message: "Successfully set up account", user, token: accessToken };
     }
   });
diff --git a/nginx/default.dev.conf b/nginx/default.dev.conf
index 2dd32049b..f1de1790c 100644
--- a/nginx/default.dev.conf
+++ b/nginx/default.dev.conf
@@ -14,7 +14,7 @@ server {
         proxy_pass http://backend:4000;
         proxy_redirect off;
 
-        proxy_cookie_path / "/; HttpOnly; SameSite=strict";
+        proxy_cookie_path / "/; SameSite=strict";
     }
 
 		location /runtime-ui-env.js {