diff --git a/README.md b/README.md
index 1f2eb2e1..c99478a1 100644
--- a/README.md
+++ b/README.md
@@ -57,7 +57,17 @@ pip install infinity-emb[all]
 ### Launch via Python
 ```Python
 from infinity_emb import create server
-create_server()
+fastapi_app = create_server()
+```
+or use the AsyncAPI directly.:
+
+```python
+from infinity_emb import AsyncEmbeddingEngine, transformer
+sentences = ["Embedded this is sentence via Infinity.", "Paris is in France."]
+engine = AsyncEmbeddingEngine(engine=transformer.InferenceEngine.torch)
+async with engine: # engine starts with engine.astart()
+    embeddings = np.array(await engine.embed(sentences))
+# engine stops with engine.astop()
 ```
 
 ### or launch the `create_server()` command via CLI
diff --git a/libs/infinity_emb/README.md b/libs/infinity_emb/README.md
index 1f2eb2e1..c99478a1 100644
--- a/libs/infinity_emb/README.md
+++ b/libs/infinity_emb/README.md
@@ -57,7 +57,17 @@ pip install infinity-emb[all]
 ### Launch via Python
 ```Python
 from infinity_emb import create server
-create_server()
+fastapi_app = create_server()
+```
+or use the AsyncAPI directly.:
+
+```python
+from infinity_emb import AsyncEmbeddingEngine, transformer
+sentences = ["Embedded this is sentence via Infinity.", "Paris is in France."]
+engine = AsyncEmbeddingEngine(engine=transformer.InferenceEngine.torch)
+async with engine: # engine starts with engine.astart()
+    embeddings = np.array(await engine.embed(sentences))
+# engine stops with engine.astop()
 ```
 
 ### or launch the `create_server()` command via CLI
diff --git a/libs/infinity_emb/infinity_emb/__init__.py b/libs/infinity_emb/infinity_emb/__init__.py
index 905b6e41..7abe263b 100644
--- a/libs/infinity_emb/infinity_emb/__init__.py
+++ b/libs/infinity_emb/infinity_emb/__init__.py
@@ -4,6 +4,7 @@
     "fastapi_schemas",
     "logger",
     "create_server",
+    "AsyncEmbeddingEngine",
     "__version__",
 ]
 import importlib.metadata
@@ -11,7 +12,7 @@
 from infinity_emb import fastapi_schemas, inference, transformer
 
 # reexports
-from infinity_emb.infinity_server import create_server
+from infinity_emb.infinity_server import AsyncEmbeddingEngine, create_server
 from infinity_emb.log_handler import logger
 
 __version__ = importlib.metadata.version("infinity_emb")
diff --git a/libs/infinity_emb/infinity_emb/inference/batch_handler.py b/libs/infinity_emb/infinity_emb/inference/batch_handler.py
index c146390a..0542778d 100644
--- a/libs/infinity_emb/infinity_emb/inference/batch_handler.py
+++ b/libs/infinity_emb/infinity_emb/inference/batch_handler.py
@@ -310,7 +310,8 @@ def _preprocess_batch(self):
                             continue
         except Exception as ex:
             logger.exception(ex)
-            exit("_preprocess_batch crashed")
+            raise ValueError("_preprocess_batch crashed")
+        self._ready = False
 
     def _core_batch(self):
         """waiting for preprocessed batches (on device)
@@ -338,7 +339,7 @@ def _core_batch(self):
                 self._feature_queue.task_done()
         except Exception as ex:
             logger.exception(ex)
-            exit("_core_batch crashed.")
+            raise ValueError("_core_batch crashed.")
 
     async def _postprocess_batch(self):
         """collecting forward(.encode) results and put them into the result store"""
@@ -379,20 +380,23 @@ async def _postprocess_batch(self):
                 self._postprocess_queue.task_done()
         except Exception as ex:
             logger.exception(ex)
-            exit("Postprocessor crashed")
+            raise ValueError("Postprocessor crashed")
 
     async def spawn(self):
         """set up the resources in batch"""
+        if self._ready:
+            raise ValueError("previous threads are still running.")
         logger.info("creating batching engine")
-        self.loop = asyncio.get_event_loop()  # asyncio.events._get_running_loop()
+        self.loop = asyncio.get_event_loop()
         self._threadpool.submit(self._preprocess_batch)
         self._threadpool.submit(self._core_batch)
         asyncio.create_task(self._postprocess_batch())
 
-    def shutdown(self):
+    async def shutdown(self):
         """
         set the shutdown event and close threadpool.
         Blocking event, until shutdown complete.
         """
         self._shutdown.set()
-        self._threadpool.shutdown(wait=True)
+        with ThreadPoolExecutor() as tp_temp:
+            await to_thread(self._threadpool.shutdown, tp_temp)
diff --git a/libs/infinity_emb/infinity_emb/infinity_server.py b/libs/infinity_emb/infinity_emb/infinity_server.py
index 2a085434..bbe37ef6 100644
--- a/libs/infinity_emb/infinity_emb/infinity_server.py
+++ b/libs/infinity_emb/infinity_emb/infinity_server.py
@@ -1,4 +1,5 @@
 import time
+from typing import List
 
 import typer
 import uvicorn
@@ -19,6 +20,106 @@
 from infinity_emb.transformer.utils import InferenceEngine, InferenceEngineTypeHint
 
 
+class AsyncEmbeddingEngine:
+    def __init__(
+        self,
+        model_name_or_path: str = "BAAI/bge-small-en-v1.5",
+        batch_size: int = 64,
+        engine: InferenceEngine = InferenceEngine.torch,
+        model_warmup=True,
+    ) -> None:
+        """Creating a Async EmbeddingEngine object.
+
+        Args:
+            model_name_or_path, str:  Defaults to "BAAI/bge-small-en-v1.5".
+            batch_size, int: Defaults to 64.
+            engine, InferenceEngine: backend for inference.
+                Defaults to InferenceEngine.torch.
+            model_warmup bool: decide which . Defaults to True.
+
+        Example:
+            ```python
+            from infinity_emb import AsyncEmbeddingEngine, transformer
+            sentences = ["Embedded this via Infinity.", "Paris is in France."]
+            engine = AsyncEmbeddingEngine(engine=transformer.InferenceEngine.torch)
+            async with engine: # engine starts with engine.astart()
+                embeddings = np.array(await engine.embed(sentences))
+            # engine stops with engine.astop().
+            # For frequent restarts, handle start/stop yourself.
+            ```
+        """
+        self.batch_size = batch_size
+        self.running = False
+        self._model, self._min_inference_t = select_model_to_functional(
+            model_name_or_path=model_name_or_path,
+            batch_size=batch_size,
+            engine=engine,
+            model_warmup=model_warmup,
+        )
+
+    async def astart(self):
+        """startup engine"""
+        self.running = True
+        self._batch_handler = BatchHandler(
+            max_batch_size=self.batch_size,
+            model=self._model,
+            verbose=logger.level <= 10,
+            batch_delay=self._min_inference_t / 2,
+        )
+        await self._batch_handler.spawn()
+
+    async def astop(self):
+        """stop engine"""
+        self.running = False
+        await self._batch_handler.shutdown()
+
+    async def __aenter__(self):
+        if self.running:
+            raise ValueError(
+                "DoubleSpawn: already started `AsyncEmbeddingEngine`. "
+                " recommended use is via AsyncContextManager"
+                " `async with engine: ..`"
+            )
+        await self.astart()
+
+    async def __aexit__(self, *args):
+        self._check_running()
+        await self.astop()
+
+    def overload_status(self):
+        self._check_running()
+        return self._batch_handler.overload_status()
+
+    def is_overloaded(self) -> bool:
+        self._check_running()
+        return self._batch_handler.is_overloaded()
+
+    async def embed(self, sentences: List[str]) -> List[List[float]]:
+        """embed multiple sentences
+
+        Args:
+            sentences (List[str]): sentences to be embedded
+
+        Raises:
+            ValueError: raised if engine is not started yet"
+
+        Returns:
+            List[List[float]]: embeddings
+                2D list-array of shape( len(sentences),embed_dim )
+        """
+        self._check_running()
+        embeddings, _ = await self._batch_handler.schedule(sentences)
+        return embeddings
+
+    def _check_running(self):
+        if not self.running:
+            raise ValueError(
+                "didn't start `AsyncEmbeddingEngine` "
+                " recommended use is via AsyncContextManager"
+                " `async with engine: ..`"
+            )
+
+
 def create_server(
     model_name_or_path: str = "BAAI/bge-small-en-v1.5",
     url_prefix: str = "/v1",
@@ -76,7 +177,7 @@ async def _startup():
 
     @app.on_event("shutdown")
     async def _shutdown():
-        app.batch_handler.shutdown()
+        await app.batch_handler.shutdown()
 
     @app.get("/ready")
     async def _ready() -> float:
diff --git a/libs/infinity_emb/infinity_emb/transformer/__init__.py b/libs/infinity_emb/infinity_emb/transformer/__init__.py
new file mode 100644
index 00000000..c5ee173e
--- /dev/null
+++ b/libs/infinity_emb/infinity_emb/transformer/__init__.py
@@ -0,0 +1,2 @@
+__all__ = ["InferenceEngine"]
+from infinity_emb.transformer.utils import InferenceEngine
diff --git a/libs/infinity_emb/tests/script_live.py b/libs/infinity_emb/tests/script_live.py
index 13f3046d..df10a1ed 100644
--- a/libs/infinity_emb/tests/script_live.py
+++ b/libs/infinity_emb/tests/script_live.py
@@ -1,5 +1,6 @@
 import concurrent.futures
 import json
+import time
 import timeit
 from functools import partial
 
@@ -58,5 +59,21 @@ def remote(json_data: bytes, iters=1):
     assert latency_st * 1.1 > latency_request
 
 
+def latency_single():
+    session = requests.Session()
+
+    def _post(i):
+        json_d = json.dumps({"input": [str(i)], "model": "model"})
+        s = time.perf_counter()
+        res = session.post(f"{LIVE_URL}/embeddings", data=json_d)
+        e = time.perf_counter()
+        assert res.status_code == 200
+        return (e - s) * 10**3
+
+    _post("hi")
+    times = [_post(i) for i in range(32)]
+    print(f"{np.median(times)}+-{np.std(times)}")
+
+
 if __name__ == "__main__":
-    embedding_live_performance()
+    latency_single()
diff --git a/libs/infinity_emb/tests/unit_test/inference/test_batch_handler.py b/libs/infinity_emb/tests/unit_test/inference/test_batch_handler.py
index 8d59fa5e..cde99c7d 100644
--- a/libs/infinity_emb/tests/unit_test/inference/test_batch_handler.py
+++ b/libs/infinity_emb/tests/unit_test/inference/test_batch_handler.py
@@ -79,15 +79,15 @@ def method_st(_sentences):
         # yappi.get_func_stats().print_all()
         # yappi.stop()
         method_st(sentences[::10])
-        time.sleep(0.2)
+        time.sleep(0.5)
         time_batch_handler = np.median(
             [(await method_batch_handler(sentences)) for _ in range(N_TIMINGS)]
         )
-        time.sleep(0.2)
+        time.sleep(0.5)
         time_st_patched = np.median(
             [method_patched(sentences) for _ in range(N_TIMINGS)]
         )
-        time.sleep(0.2)
+        time.sleep(0.5)
         time_st = np.median([method_st(sentences) for _ in range(N_TIMINGS)])
 
         print(
@@ -113,4 +113,4 @@ def method_st(_sentences):
         )
 
     finally:
-        bh.shutdown()
+        await bh.shutdown()
diff --git a/libs/infinity_emb/tests/unit_test/test_infinity_server.py b/libs/infinity_emb/tests/unit_test/test_infinity_server.py
index 23765710..f46deab9 100644
--- a/libs/infinity_emb/tests/unit_test/test_infinity_server.py
+++ b/libs/infinity_emb/tests/unit_test/test_infinity_server.py
@@ -1,9 +1,12 @@
 import subprocess
 
+import numpy as np
+import pytest
 import typer
 import uvicorn
 from fastapi import FastAPI
 
+from infinity_emb import AsyncEmbeddingEngine, transformer
 from infinity_emb.infinity_server import (
     UVICORN_LOG_LEVELS,
     InferenceEngineTypeHint,
@@ -14,6 +17,38 @@
 from infinity_emb.transformer.utils import InferenceEngine
 
 
+@pytest.mark.anyio
+async def test_async_api_debug():
+    sentences = ["Embedded this is sentence via Infinity.", "Paris is in France."]
+    engine = AsyncEmbeddingEngine(engine=transformer.InferenceEngine.debugengine)
+    async with engine:
+        embeddings = np.array(await engine.embed(sentences))
+        assert embeddings.shape[0] == len(sentences)
+        assert embeddings.shape[1] >= 10
+        for idx, s in enumerate(sentences):
+            assert embeddings[idx][0] == len(s), f"{embeddings}, {s}"
+
+
+@pytest.mark.anyio
+async def test_async_api_torch():
+    sentences = ["Hi", "how"]
+    engine = AsyncEmbeddingEngine(engine=transformer.InferenceEngine.torch)
+    async with engine:
+        embeddings = np.array(await engine.embed(sentences))
+        assert embeddings.shape[0] == 2
+        assert embeddings.shape[1] >= 10
+
+
+@pytest.mark.anyio
+async def test_async_api_fastembed():
+    sentences = ["Hi", "how"]
+    engine = AsyncEmbeddingEngine(engine=transformer.InferenceEngine.fastembed)
+    async with engine:
+        embeddings = np.array(await engine.embed(sentences))
+        assert embeddings.shape[0] == 2
+        assert embeddings.shape[1] >= 10
+
+
 def test_cli_help():
     log = subprocess.run(["infinity_emb", "--help"])
     assert log.returncode == 0