diff --git a/backend/src/controllers/stream.controller.ts b/backend/src/controllers/stream.controller.ts
index 7823c9e9..8a908b9c 100644
--- a/backend/src/controllers/stream.controller.ts
+++ b/backend/src/controllers/stream.controller.ts
@@ -598,6 +598,13 @@ export const topUpStreamHandler = async (req: Request, res: Response) => {
       return res.status(403).json({ error: 'Only the stream sender may top up this stream' });
     }
 
+    if (!stream.isActive) {
+      return res.status(409).json({ error: 'Conflict', message: 'Cannot top up an inactive stream' });
+    }
+    if (stream.isPaused) {
+      return res.status(409).json({ error: 'Conflict', message: 'Cannot top up a paused stream' });
+    }
+
     const txHash = await topUpStream(streamId, amount, callerAddress);
 
     const newDeposited = (BigInt(stream.depositedAmount) + amount).toString();
diff --git a/backend/tests/integration/top-up.test.ts b/backend/tests/integration/top-up.test.ts
index e6549e8f..9c42e2af 100644
--- a/backend/tests/integration/top-up.test.ts
+++ b/backend/tests/integration/top-up.test.ts
@@ -161,4 +161,28 @@ describe('POST /v1/streams/:streamId/top-up', () => {
       }),
     );
   });
+
+  it('returns 409 when stream is inactive', async () => {
+    vi.mocked(mockPrisma.stream.findUnique).mockResolvedValue({ ...mockStream, isActive: false } as any);
+
+    const res = await request(app)
+      .post('/v1/streams/42/top-up')
+      .set('Authorization', 'Bearer dummy')
+      .send({ amount: '1000' });
+
+    expect(res.status).toBe(409);
+    expect(res.body.message).toMatch(/inactive stream/);
+  });
+
+  it('returns 409 when stream is paused', async () => {
+    vi.mocked(mockPrisma.stream.findUnique).mockResolvedValue({ ...mockStream, isPaused: true } as any);
+
+    const res = await request(app)
+      .post('/v1/streams/42/top-up')
+      .set('Authorization', 'Bearer dummy')
+      .send({ amount: '1000' });
+
+    expect(res.status).toBe(409);
+    expect(res.body.message).toMatch(/paused stream/);
+  });
 });