diff --git a/CHANGELOG.md b/CHANGELOG.md
index d67263859..d860867f4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- Fixed the public offers endpoint returning a JSON body with a `text/plain` content type. [#1670](https://github.com/sourcebot-dev/sourcebot/pull/1670)
+
 ## [5.1.14] - 2026-09-17
 
 ### Added
diff --git a/packages/web/src/app/api/(server)/offers/route.test.ts b/packages/web/src/app/api/(server)/offers/route.test.ts
new file mode 100644
index 000000000..118d6c2e0
--- /dev/null
+++ b/packages/web/src/app/api/(server)/offers/route.test.ts
@@ -0,0 +1,47 @@
+import { NextRequest } from "next/server";
+import { beforeEach, describe, expect, test, vi } from "vitest";
+
+const mocks = vi.hoisted(() => ({
+    offers: vi.fn(),
+}));
+
+vi.mock("@/features/billing/client", () => ({
+    client: {
+        offers: mocks.offers,
+    },
+}));
+
+vi.mock("@sourcebot/shared", () => ({
+    env: {
+        SOURCEBOT_INSTALL_ID: "install-id",
+    },
+}));
+
+vi.mock("@/lib/posthog", () => ({
+    captureEvent: vi.fn(),
+}));
+
+const importRoute = async () => {
+    vi.resetModules();
+    return import("./route");
+};
+
+describe("GET /api/offers", () => {
+    beforeEach(() => {
+        vi.clearAllMocks();
+    });
+
+    test("returns offers as JSON", async () => {
+        const offers = [{ id: "startup" }];
+        mocks.offers.mockResolvedValue(offers);
+        const { GET } = await importRoute();
+
+        const response = await GET(new NextRequest("https://sourcebot.example.com/api/offers"));
+
+        expect(mocks.offers).toHaveBeenCalledTimes(1);
+        expect(mocks.offers).toHaveBeenCalledWith({ installId: "install-id" });
+        expect(response.headers.get("content-type")).toContain("application/json");
+        expect(response.headers.get("cache-control")).toBe("public, max-age=300");
+        await expect(response.json()).resolves.toEqual(offers);
+    });
+});
diff --git a/packages/web/src/app/api/(server)/offers/route.ts b/packages/web/src/app/api/(server)/offers/route.ts
index aff748d5d..bae6e4911 100644
--- a/packages/web/src/app/api/(server)/offers/route.ts
+++ b/packages/web/src/app/api/(server)/offers/route.ts
@@ -8,9 +8,9 @@ export const GET = apiHandler(async () => {
         installId: env.SOURCEBOT_INSTALL_ID,
     });
 
-    return new Response(JSON.stringify(offers), {
+    return Response.json(offers, {
         headers: {
             'Cache-Control': 'public, max-age=300'
         }
     });
-})
\ No newline at end of file
+})