diff --git a/docs/features/sleep_mode.md b/docs/features/sleep_mode.md
index 41aa48c1735..5016632cbab 100644
--- a/docs/features/sleep_mode.md
+++ b/docs/features/sleep_mode.md
@@ -37,3 +37,26 @@ Example:
 ```python
 omni = Omni(model=...,enable_sleep_mode=True)
 ```
+
+## API Usage
+
+### Sleep
+To sleep current model, it can release GPU memory.
+
+```
+POST /sleep?level=1
+```
+
+### Wake Up
+To wake up current sleep model, it can occupancy GPU memory.
+
+```
+POST /wake_up
+```
+
+### Get Sleep info
+To search current model sleep info, about sleep level and whether sleep.
+
+```
+GET /sleep_info
+```
diff --git a/tests/entrypoints/openai_api/test_sleep_api.py b/tests/entrypoints/openai_api/test_sleep_api.py
new file mode 100644
index 00000000000..3b27a4ced4c
--- /dev/null
+++ b/tests/entrypoints/openai_api/test_sleep_api.py
@@ -0,0 +1,95 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from argparse import Namespace
+from http import HTTPStatus
+
+import pytest
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from vllm_omni.entrypoints.openai.api_server import sleep_router
+
+
+class FakeEngine:
+    """Full-featured stub that records calls and tracks sleep state."""
+
+    def __init__(self):
+        self._is_sleeping = False
+        self._sleep_level: int | None = None
+        self.sleep_calls: list[tuple] = []  # [(level, mode), ...]
+        self.wake_up_calls: list[tuple] = []  # [(tags,), ...]
+
+    async def sleep(self, level: int = 1, mode: str = "abort") -> None:
+        self._is_sleeping = True
+        self._sleep_level = level
+        self.sleep_calls.append((level, mode))
+
+    async def wake_up(self, tags: list[str] | None = None) -> None:
+        self._is_sleeping = False
+        self._sleep_level = None
+        self.wake_up_calls.append((tags,))
+
+    async def is_sleeping(self) -> bool:
+        return self._is_sleeping
+
+    async def sleep_level(self) -> int:
+        return self._sleep_level
+
+
+@pytest.fixture
+def client() -> TestClient:
+    app = FastAPI()
+    app.include_router(sleep_router)
+    app.state.engine_client = FakeEngine()
+    app.state.args = Namespace(enable_sleep_mode=True)
+    return TestClient(app, raise_server_exceptions=False)
+
+
+def test_sleep(client: TestClient):
+    assert client.post("/sleep?level=1").status_code == HTTPStatus.OK
+
+    client.post("/sleep?level=1")
+    engine: FakeEngine = client.app.state.engine_client
+    level, model = engine.sleep_calls[-1]
+    assert level == 1
+    assert model == "abort"
+
+    assert client.post("/sleep?level=3").status_code == HTTPStatus.BAD_REQUEST
+    assert client.post("/sleep?level=abc").status_code == HTTPStatus.BAD_REQUEST
+
+    client.post("/sleep?level=2&mode=drain")
+    engine: FakeEngine = client.app.state.engine_client
+    level, model = engine.sleep_calls[-1]
+    assert level == 2
+    assert model == "abort"
+
+
+def test_wakeup(client: TestClient):
+    assert client.post("/wake_up").status_code == HTTPStatus.OK
+
+    client.post("/wake_up")
+    engine: FakeEngine = client.app.state.engine_client
+    assert not engine._is_sleeping
+
+    client.post("/wake_up?tags=")
+    engine: FakeEngine = client.app.state.engine_client
+    assert engine.wake_up_calls[-1] == ([""],)
+
+    client.post("/wake_up?tags=weights")
+    engine: FakeEngine = client.app.state.engine_client
+    assert engine.wake_up_calls[-1] == (["weights"],)
+
+
+def test_sleep_info(client: TestClient):
+    client.post("/sleep?level=1")
+    assert client.get("/sleep_info").status_code == HTTPStatus.OK
+
+    client.post("/wake_up")
+    assert client.get("/sleep_info").json() == {"sleep_level": None, "is_sleeping": False}
+
+    client.post("/sleep?level=1")
+    assert client.get("/sleep_info").json() == {"sleep_level": 1, "is_sleeping": True}
+
+    client.post("/sleep?level=2")
+    assert client.get("/sleep_info").json() == {"sleep_level": 2, "is_sleeping": True}
diff --git a/vllm_omni/entrypoints/async_omni.py b/vllm_omni/entrypoints/async_omni.py
index 129ef3c99d8..2af89241e59 100644
--- a/vllm_omni/entrypoints/async_omni.py
+++ b/vllm_omni/entrypoints/async_omni.py
@@ -75,6 +75,7 @@ def __init__(self, *args: Any, model: str = "", **kwargs: Any) -> None:
         self._pause_cond: asyncio.Condition = asyncio.Condition()
         self._paused: bool = False
         self._is_sleeping: bool = False
+        self._sleep_level: int = None
         self.final_output_task: asyncio.Task | None = None
 
         self.config_path = self.engine.config_path
@@ -648,6 +649,7 @@ async def sleep(self, level: int = 1, mode: PauseMode = "abort") -> None:
         Best-effort: unsupported stages will emit a TODO result.
         """
         self._is_sleeping = True
+        self._sleep_level = level
         await self.collective_rpc(method="sleep", args=(level,))
 
     async def wake_up(self, tags: list[str] | None = None) -> None:
@@ -656,6 +658,7 @@ async def wake_up(self, tags: list[str] | None = None) -> None:
         Best-effort: unsupported stages will emit a TODO result.
         """
         self._is_sleeping = False
+        self._sleep_level = -1
         await self.collective_rpc(method="wake_up", args=(tags,))
 
     async def is_sleeping(self) -> bool:
@@ -666,6 +669,9 @@ async def is_sleeping(self) -> bool:
         """
         return self._is_sleeping
 
+    async def sleep_level(self) -> int:
+        return self._sleep_level
+
     async def add_lora(self, lora_request: LoRARequest) -> bool:
         """Load a new LoRA adapter into all stages.
 
diff --git a/vllm_omni/entrypoints/openai/api_server.py b/vllm_omni/entrypoints/openai/api_server.py
index defaa9822cc..6c794388730 100644
--- a/vllm_omni/entrypoints/openai/api_server.py
+++ b/vllm_omni/entrypoints/openai/api_server.py
@@ -121,6 +121,7 @@
 router = APIRouter()
 
 profiler_router = APIRouter()
+sleep_router = APIRouter()
 
 
 def _should_enable_profiler_endpoints(stage_configs: list | None) -> bool:
@@ -313,6 +314,11 @@ async def omni_run_server_worker(listen_address, sock, args, client_config=None,
             logger.warning("Profiler endpoints are enabled. This should ONLY be used for local development!")
             app.include_router(profiler_router)
 
+        # Conditionally register sleep endpoints
+        if args.enable_sleep_mode:
+            logger.info("Sleep endpoints are enabled.")
+            app.include_router(sleep_router)
+
         vllm_config = await _get_vllm_config(engine_client)
 
         # Check if pure diffusion mode (vllm_config will be None)
@@ -2405,3 +2411,80 @@ async def stop_profile(raw_request: Request, request: ProfileRequest | None = No
         raise HTTPException(
             status_code=HTTPStatus.INTERNAL_SERVER_ERROR.value, detail=f"Failed to stop profiler: {str(e)}"
         )
+
+
+@sleep_router.post("/sleep")
+async def sleep(raw_request: Request):
+    raw_level = raw_request.query_params.get("level", "1")
+    _VALID_LEVELS = {1, 2}
+    try:
+        level = int(raw_level)
+    except ValueError:
+        raise HTTPException(
+            status_code=HTTPStatus.BAD_REQUEST.value,
+            detail=f"Invalid 'level' value {raw_level!r}: must be an integer.",
+        )
+    if level not in _VALID_LEVELS:
+        raise HTTPException(
+            status_code=HTTPStatus.BAD_REQUEST.value,
+            detail=f"Invalid 'level' value {level}: must be one of {sorted(_VALID_LEVELS)}.",
+        )
+    try:
+        engine_client = raw_request.app.state.engine_client
+        await engine_client.sleep(int(level))
+        return JSONResponse(content="ok")
+    except Exception as e:
+        logger.exception("Failed to sleep model: %s", e)
+        raise HTTPException(
+            status_code=HTTPStatus.INTERNAL_SERVER_ERROR.value,
+            detail=f"Failed to sleep model: {e}",
+        )
+
+
+@sleep_router.post("/wake_up")
+async def wake_up(raw_request: Request):
+    """
+    Wake up the worker from sleep mode. See the sleep function
+    method for more details.
+
+    Args:
+        tags: An optional list of tags to reallocate the worker memory
+            for specific memory allocations. Values must be in
+            `("weights")`. If None, all memory is reallocated.
+            wake_up should be called with all tags (or None) before the
+            worker is used again.
+    """
+    tags = raw_request.query_params.getlist("tags")
+    if tags == []:
+        tags = None
+    try:
+        engine_client = raw_request.app.state.engine_client
+        await engine_client.wake_up(tags)
+        return JSONResponse(content="ok")
+    except Exception as e:
+        logger.exception("Failed to wake_up model: %s", e)
+        raise HTTPException(
+            status_code=HTTPStatus.INTERNAL_SERVER_ERROR.value,
+            detail=f"Failed to wake_up model: {e}",
+        )
+
+
+@sleep_router.get("/sleep_info")
+async def sleep_info(raw_request: Request) -> JSONResponse:
+    """Return the current sleep level of the engine.
+
+    Response body: ``{"sleep_level": int | null}``
+        - ``null``   engine is awake (not sleeping).
+        - ``1``      weights are offloaded.
+        - ``2``      weights offloaded and KV caches saved/reset.
+    """
+    try:
+        engine_client = raw_request.app.state.engine_client
+        level = await engine_client.sleep_level()
+        result = await engine_client.is_sleeping()
+    except Exception as e:
+        raise HTTPException(
+            status_code=HTTPStatus.INTERNAL_SERVER_ERROR.value,
+            detail=f"Failed to query sleep level: {e}",
+        )
+    return JSONResponse(content={"sleep_level": level, "is_sleeping": result})