diff --git a/apps/gittensory-ui/wrangler.jsonc b/apps/gittensory-ui/wrangler.jsonc
index ba4046e5ee..cd8daab4a9 100644
--- a/apps/gittensory-ui/wrangler.jsonc
+++ b/apps/gittensory-ui/wrangler.jsonc
@@ -27,5 +27,10 @@
       "pattern": "gittensory.aethereal.dev",
       "custom_domain": true,
     },
+    // LoopOver rebrand (issue #4762, Step 1): live side-by-side with the domain above, not a replacement yet.
+    {
+      "pattern": "loopover.ai",
+      "custom_domain": true,
+    },
   ],
 }
diff --git a/src/auth/github-oauth.ts b/src/auth/github-oauth.ts
index ed37eebd18..46f0ae931d 100644
--- a/src/auth/github-oauth.ts
+++ b/src/auth/github-oauth.ts
@@ -245,8 +245,13 @@ function normalizeReturnTo(env: Env, value: string | undefined): string {
     // two lines up), so a separate hardcoded entry here was dead weight once a self-hoster sets their own
     // PUBLIC_SITE_ORIGIN -- it kept accepting the cloud origin as a valid redirect target even for a self-host
     // instance that never uses it (#4615). Rely solely on siteOrigin.
+    const aliasOrigins = (env.PUBLIC_SITE_ORIGIN_ALIASES ?? "")
+      .split(",")
+      .map((alias) => alias.trim().replace(/\/$/, ""))
+      .filter(Boolean);
     const allowedOrigins = new Set([
       siteOrigin.replace(/\/$/, ""),
+      ...aliasOrigins,
       "http://localhost:3000",
       "http://localhost:4173",
       "http://localhost:5173",
diff --git a/src/env.d.ts b/src/env.d.ts
index 60b7e54c1c..4416a6d542 100644
--- a/src/env.d.ts
+++ b/src/env.d.ts
@@ -72,6 +72,12 @@ declare global {
      *  Deliberately NOT declared in this chunk; the review path keeps its current concurrency behavior. */
     PUBLIC_API_ORIGIN?: string;
     PUBLIC_SITE_ORIGIN?: string;
+    /** Comma-separated extra origins (each `scheme://host[:port]`) allowed as a post-GitHub-OAuth `returnTo`
+     *  redirect target, alongside PUBLIC_SITE_ORIGIN. Lets the web login flow work correctly from more than
+     *  one live UI domain at once (e.g. during a brand/domain migration) without breaking PUBLIC_SITE_ORIGIN's
+     *  single-value override contract for self-hosters. Unset ⇒ only PUBLIC_SITE_ORIGIN (+ localhost) is
+     *  allowed, exactly as before this var existed. */
+    PUBLIC_SITE_ORIGIN_ALIASES?: string;
     AI_SUMMARIES_ENABLED?: string;
     AI_PUBLIC_COMMENTS_ENABLED?: string;
     /** Model id for a genuine Cloudflare Workers AI binding only — no live deployment (hosted or self-host)
diff --git a/test/unit/auth.test.ts b/test/unit/auth.test.ts
index d22ea0c725..ec7c2d0657 100644
--- a/test/unit/auth.test.ts
+++ b/test/unit/auth.test.ts
@@ -789,6 +789,41 @@ describe("private-beta auth and rate limiting", () => {
     expect(local.returnTo).toBe("http://localhost:5173/app");
   });
 
+  it("PUBLIC_SITE_ORIGIN_ALIASES lets a login started on a second live domain return to that same domain (#4762)", async () => {
+    const env = createTestEnv({
+      GITHUB_OAUTH_CLIENT_ID: "client-id",
+      GITHUB_OAUTH_CLIENT_SECRET: "client-secret",
+      PUBLIC_SITE_ORIGIN: "https://gittensory.aethereal.dev",
+      PUBLIC_SITE_ORIGIN_ALIASES: "https://loopover.ai, https://staging.loopover.ai",
+    });
+
+    // The primary PUBLIC_SITE_ORIGIN still works exactly as before.
+    const primary = await startGitHubWebOAuth(env, "https://gittensory-api.aethereal.dev/v1/auth/github/start", "https://gittensory.aethereal.dev/app/workbench");
+    expect(primary.returnTo).toBe("https://gittensory.aethereal.dev/app/workbench");
+
+    // An aliased origin is accepted verbatim, not bounced to the primary origin's fallback.
+    const alias = await startGitHubWebOAuth(env, "https://gittensory-api.aethereal.dev/v1/auth/github/start", "https://loopover.ai/app/workbench");
+    expect(alias.returnTo).toBe("https://loopover.ai/app/workbench");
+
+    // A second, comma-separated alias (with surrounding whitespace) is also accepted.
+    const secondAlias = await startGitHubWebOAuth(env, "https://gittensory-api.aethereal.dev/v1/auth/github/start", "https://staging.loopover.ai/app");
+    expect(secondAlias.returnTo).toBe("https://staging.loopover.ai/app");
+
+    // An origin that is neither the primary nor an alias still falls back to the primary origin's /app.
+    const untrusted = await startGitHubWebOAuth(env, "https://gittensory-api.aethereal.dev/v1/auth/github/start", "https://evil.example/app");
+    expect(untrusted.returnTo).toBe("https://gittensory.aethereal.dev/app");
+
+    // Unset PUBLIC_SITE_ORIGIN_ALIASES behaves exactly as before this var existed -- only the primary origin.
+    const noAliases = createTestEnv({
+      GITHUB_OAUTH_CLIENT_ID: "client-id",
+      GITHUB_OAUTH_CLIENT_SECRET: "client-secret",
+      PUBLIC_SITE_ORIGIN: "https://gittensory.aethereal.dev",
+    });
+    delete (noAliases as Partial<Env>).PUBLIC_SITE_ORIGIN_ALIASES;
+    const rejected = await startGitHubWebOAuth(noAliases, "https://gittensory-api.aethereal.dev/v1/auth/github/start", "https://loopover.ai/app/workbench");
+    expect(rejected.returnTo).toBe("https://gittensory.aethereal.dev/app");
+  });
+
   it("verifies the GitHub token audience before minting a session on the token-exchange path", async () => {
     const env = createTestEnv({ GITHUB_OAUTH_CLIENT_ID: "client-id", GITHUB_OAUTH_CLIENT_SECRET: "client-secret" });
     const introspect = (appClientId: string | undefined) =>
diff --git a/worker-configuration.d.ts b/worker-configuration.d.ts
index 405ed4928a..34e9be5122 100644
--- a/worker-configuration.d.ts
+++ b/worker-configuration.d.ts
@@ -1,5 +1,5 @@
 /* eslint-disable */
-// Generated by Wrangler by running `wrangler types` (hash: 902e76d8bfe7cb797b601690c9e44c8d)
+// Generated by Wrangler by running `wrangler types` (hash: d5851e3e7ea2bc8cd084f39b4328cb86)
 // Runtime types generated with workerd@1.20260701.1 2026-05-28 nodejs_compat
 interface __BaseEnv_Env {
 	DB: D1Database;
@@ -14,6 +14,7 @@ interface __BaseEnv_Env {
 	GITTENSORY_DRIFT_ISSUE_REPO: "JSONbored/gittensory";
 	PUBLIC_API_ORIGIN: "https://gittensory-api.aethereal.dev";
 	PUBLIC_SITE_ORIGIN: "https://gittensory.aethereal.dev";
+	PUBLIC_SITE_ORIGIN_ALIASES: "https://loopover.ai";
 	ADMIN_GITHUB_LOGINS: "JSONbored";
 	GITTENSORY_REVIEW_UNIFIED_COMMENT: "false";
 	GITTENSORY_REVIEW_INLINE_COMMENTS: "false";
@@ -102,6 +103,7 @@ declare namespace NodeJS {
 		| "PUBLIC_API_ORIGIN"
 		| "PUBLIC_REPO_STATS_ALLOWLIST"
 		| "PUBLIC_SITE_ORIGIN"
+		| "PUBLIC_SITE_ORIGIN_ALIASES"
 		| "SCORING_TIME_DECAY_ENABLED"
 	>> {}
 }
diff --git a/wrangler.jsonc b/wrangler.jsonc
index 89099f1323..1fb51b625f 100644
--- a/wrangler.jsonc
+++ b/wrangler.jsonc
@@ -40,6 +40,9 @@
     "GITTENSORY_DRIFT_ISSUE_REPO": "JSONbored/gittensory",
     "PUBLIC_API_ORIGIN": "https://gittensory-api.aethereal.dev",
     "PUBLIC_SITE_ORIGIN": "https://gittensory.aethereal.dev",
+    // LoopOver rebrand (issue #4762, Step 1): loopover.ai runs live side-by-side with the existing domain, not
+    // as a replacement -- keeps the post-OAuth-login redirect working when a user signs in from loopover.ai.
+    "PUBLIC_SITE_ORIGIN_ALIASES": "https://loopover.ai",
     "ADMIN_GITHUB_LOGINS": "JSONbored",
     // Hosted reviews are retired. Cloudflare now serves the public API + Orb broker only; review execution runs
     // in the self-host container, where Redis-backed transient state is mandatory. The Cloudflare API worker no
@@ -226,6 +229,11 @@
       "pattern": "gittensory-api.aethereal.dev",
       "custom_domain": true,
     },
+    // LoopOver rebrand (issue #4762, Step 1): live side-by-side with the domain above, not a replacement yet.
+    {
+      "pattern": "api.loopover.ai",
+      "custom_domain": true,
+    },
   ],
   "d1_databases": [
     {