diff --git a/app/api/upload/route.ts b/app/api/upload/route.ts
new file mode 100644
index 000000000..3d865e965
--- /dev/null
+++ b/app/api/upload/route.ts
@@ -0,0 +1,33 @@
+import { NextRequest, NextResponse } from "next/server";
+import { getCorsHeaders } from "@/lib/networking/getCorsHeaders";
+import { uploadFileHandler } from "@/lib/arweave/uploadFileHandler";
+
+/**
+ * OPTIONS handler for CORS preflight requests.
+ *
+ * @returns A NextResponse with CORS headers.
+ */
+export async function OPTIONS() {
+  return new NextResponse(null, {
+    status: 200,
+    headers: getCorsHeaders(),
+  });
+}
+
+/**
+ * POST /api/upload
+ *
+ * Uploads a file (multipart/form-data, field name `file`) to Arweave and
+ * returns the gateway URL.
+ *
+ * @param request - The incoming request carrying the file.
+ * @returns A NextResponse with `{ success, fileName, fileType, fileSize, url }` on 200
+ *   or `{ success: false, error }` on 500.
+ */
+export async function POST(request: NextRequest) {
+  return uploadFileHandler(request);
+}
+
+export const dynamic = "force-dynamic";
+export const fetchCache = "force-no-store";
+export const revalidate = 0;
diff --git a/lib/arweave/__tests__/uploadFileHandler.test.ts b/lib/arweave/__tests__/uploadFileHandler.test.ts
new file mode 100644
index 000000000..659059cf5
--- /dev/null
+++ b/lib/arweave/__tests__/uploadFileHandler.test.ts
@@ -0,0 +1,96 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { NextRequest } from "next/server";
+import { uploadFileHandler } from "@/lib/arweave/uploadFileHandler";
+import { uploadToArweave } from "@/lib/arweave/uploadToArweave";
+import { getFetchableUrl } from "@/lib/arweave/getFetchableUrl";
+
+vi.mock("@/lib/networking/getCorsHeaders", () => ({
+  getCorsHeaders: vi.fn(() => ({ "Access-Control-Allow-Origin": "*" })),
+}));
+
+vi.mock("@/lib/arweave/uploadToArweave", () => ({
+  uploadToArweave: vi.fn(),
+}));
+
+vi.mock("@/lib/arweave/getFetchableUrl", () => ({
+  getFetchableUrl: vi.fn(),
+}));
+
+const buildRequest = (formData: FormData) =>
+  new NextRequest("https://example.com/api/upload", {
+    method: "POST",
+    body: formData,
+  });
+
+describe("uploadFileHandler", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("uploads the file and returns the gateway URL", async () => {
+    vi.mocked(uploadToArweave).mockResolvedValue({ id: "tx_abc" } as never);
+    vi.mocked(getFetchableUrl).mockReturnValue("https://arweave.net/tx_abc");
+
+    const file = new File([new Uint8Array([1, 2, 3, 4])], "hello.png", {
+      type: "image/png",
+    });
+    const formData = new FormData();
+    formData.append("file", file);
+
+    const response = await uploadFileHandler(buildRequest(formData));
+    const body = await response.json();
+
+    expect(response.status).toBe(200);
+    expect(uploadToArweave).toHaveBeenCalledWith(expect.any(Buffer), "image/png");
+    const [bufferArg] = vi.mocked(uploadToArweave).mock.calls[0];
+    expect((bufferArg as Buffer).length).toBe(4);
+    expect(getFetchableUrl).toHaveBeenCalledWith("ar://tx_abc");
+    expect(body).toEqual({
+      success: true,
+      fileName: "hello.png",
+      fileType: "image/png",
+      fileSize: 4,
+      url: "https://arweave.net/tx_abc",
+    });
+  });
+
+  it("falls back to application/octet-stream when file.type is empty", async () => {
+    vi.mocked(uploadToArweave).mockResolvedValue({ id: "tx_xyz" } as never);
+    vi.mocked(getFetchableUrl).mockReturnValue("https://arweave.net/tx_xyz");
+
+    const file = new File([new Uint8Array([9])], "blob.bin", { type: "" });
+    const formData = new FormData();
+    formData.append("file", file);
+
+    const response = await uploadFileHandler(buildRequest(formData));
+    const body = await response.json();
+
+    expect(response.status).toBe(200);
+    expect(uploadToArweave).toHaveBeenCalledWith(expect.any(Buffer), "application/octet-stream");
+    expect(body.fileType).toBe("application/octet-stream");
+  });
+
+  it("returns 500 with success:false when no file is provided", async () => {
+    const formData = new FormData();
+    const response = await uploadFileHandler(buildRequest(formData));
+    const body = await response.json();
+
+    expect(response.status).toBe(500);
+    expect(body).toEqual({ success: false, error: "No file provided" });
+    expect(uploadToArweave).not.toHaveBeenCalled();
+  });
+
+  it("returns 500 with success:false when uploadToArweave throws", async () => {
+    vi.mocked(uploadToArweave).mockRejectedValue(new Error("network down"));
+
+    const file = new File([new Uint8Array([1])], "x.png", { type: "image/png" });
+    const formData = new FormData();
+    formData.append("file", file);
+
+    const response = await uploadFileHandler(buildRequest(formData));
+    const body = await response.json();
+
+    expect(response.status).toBe(500);
+    expect(body).toEqual({ success: false, error: "network down" });
+  });
+});
diff --git a/lib/arweave/uploadFileHandler.ts b/lib/arweave/uploadFileHandler.ts
new file mode 100644
index 000000000..51218f846
--- /dev/null
+++ b/lib/arweave/uploadFileHandler.ts
@@ -0,0 +1,58 @@
+import { NextRequest, NextResponse } from "next/server";
+import { getCorsHeaders } from "@/lib/networking/getCorsHeaders";
+import { uploadToArweave } from "@/lib/arweave/uploadToArweave";
+import { getFetchableUrl } from "@/lib/arweave/getFetchableUrl";
+
+/**
+ * Handles POST /api/upload — uploads a file to Arweave and returns a gateway URL.
+ *
+ * Mirrors the chat-side response shape exactly so callers can migrate
+ * with a single base-URL swap.
+ *
+ * @param request - The incoming request carrying multipart/form-data with a `file` field.
+ * @returns A NextResponse with `{ success, fileName, fileType, fileSize, url }` on 200
+ *   or `{ success: false, error }` on 500.
+ */
+export async function uploadFileHandler(request: NextRequest): Promise<NextResponse> {
+  try {
+    const formData = await request.formData();
+    const file = formData.get("file");
+
+    if (!file || typeof file === "string") {
+      throw new Error("No file provided");
+    }
+
+    const fileBuffer = Buffer.from(await file.arrayBuffer());
+    const fileSize = fileBuffer.length;
+    const fileType = file.type || "application/octet-stream";
+    const fileName = file.name;
+
+    const transaction = await uploadToArweave(fileBuffer, fileType);
+
+    return NextResponse.json(
+      {
+        success: true,
+        fileName,
+        fileType,
+        fileSize,
+        url: getFetchableUrl(`ar://${transaction.id}`),
+      },
+      {
+        status: 200,
+        headers: getCorsHeaders(),
+      },
+    );
+  } catch (error) {
+    console.error("/api/upload error", error);
+    return NextResponse.json(
+      {
+        success: false,
+        error: error instanceof Error ? error.message : "Unknown error",
+      },
+      {
+        status: 500,
+        headers: getCorsHeaders(),
+      },
+    );
+  }
+}