diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index aebb248..f9d834e 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -5,10 +5,10 @@ repos:
     - id: black
       language_version: python3
 -   repo: https://github.com/pycqa/flake8
-    rev: 4.0.1
+    rev: 3.9.0
     hooks:
     - id: flake8
 -   repo: https://github.com/timothycrosley/isort
-    rev: 5.9.3
+    rev: 5.12.0
     hooks:
     - id: isort
\ No newline at end of file
diff --git a/app/api/api_v1/routers/s3_checks.py b/app/api/api_v1/routers/s3_checks.py
index 2992df9..ea86db3 100644
--- a/app/api/api_v1/routers/s3_checks.py
+++ b/app/api/api_v1/routers/s3_checks.py
@@ -1,20 +1,23 @@
 from typing import List, Union
 
 from fastapi import APIRouter, Form, HTTPException, status
-from fastapi.logger import logger
 
 from app.core.config import Settings
-from app.models.s3_checks import s3FileCheck, s3FileCheckResponse
-from app.utils.s3_checks import get_s3_resource
+from app.utils.s3_checks import (
+    check_file_metadata,
+    check_files_metadata,
+    get_s3_resource,
+)
 
 s3_router = router = APIRouter()
 settings = Settings()
 
 
-@router.post("/files/key/", response_model=s3FileCheck)
+@router.post(
+    "/files/key/",
+)
 async def check_if_file_exist_in_bucket(
     file_key: str = Form(...),
-    bucket: str = Form(...),
     s3_access_key: Union[str, None] = Form(
         None,
         description="S3 access key. If None then take the default one from env variables",
@@ -64,29 +67,15 @@ async def check_if_file_exist_in_bucket(
             detail=f"Error connecting to S3: {e}",
         )
     else:
-        is_exist = False
-        bucket = s3_resource.Bucket(bucket)
-        if bucket in s3_resource.buckets.all():
-            objs = list(bucket.objects.filter(Prefix=file_key))
-            logger.info(f"Checking if file exist in bucket: {file_key}")
-            if len(objs) == 1 and objs[0].key == file_key:
-                is_exist = True
-            return {
-                "file_key": file_key,
-                "is_exists": is_exist,
-            }
-        else:
-            logger.info(f"Bucket {bucket} does not exist")
-            raise HTTPException(
-                status_code=status.HTTP_400_BAD_REQUEST,
-                detail="Bucket does not exist",
-            )
+        file_metadata = await check_file_metadata(s3_resource, file_key)
+        return file_metadata
 
 
-@router.post("/files", response_model=s3FileCheckResponse)
+@router.post(
+    "/files",
+)
 async def check_if_files_exist_in_bucket(
     file_keys: List[str] = Form(...),
-    bucket: str = Form(...),
     s3_access_key: Union[str, None] = Form(
         None,
         description="S3 access key. If None then take the default one from env variables",
@@ -138,36 +127,8 @@ async def check_if_files_exist_in_bucket(
             file_keys = [key for key in file_keys[0].split(",")]
         file_keys_set = set(file_keys)
 
-        bucket = s3_resource.Bucket(bucket)
-
-        if bucket in s3_resource.buckets.all():
-            logger.debug("Bucket exists: {}".format(bucket))
-
-            folders = set([key.split("/")[0] for key in file_keys_set])
-            all_s3_objects = []
-            for folder in folders:
-                objects_in_folder = [
-                    {"key": obj.key, "size": obj.size}
-                    for obj in bucket.objects.filter(Prefix=folder).all()
-                ]
-                all_s3_objects = all_s3_objects + objects_in_folder
-
-            existing_keys = file_keys_set.intersection(
-                [obj["key"] for obj in all_s3_objects]
-            )
-            non_existing_keys = set(file_keys).difference(existing_keys)
-            existing_file_details = [
-                obj for obj in all_s3_objects if obj["key"] in existing_keys
-            ]
-
-            return {
-                "exists": existing_file_details,
-                "non_exists": list(non_existing_keys),
-            }
+        files_metadata = await check_files_metadata(
+            session=s3_resource, file_keys=file_keys_set
+        )
 
-        else:
-            logger.info(f"Bucket {bucket} does not exist")
-            raise HTTPException(
-                status_code=status.HTTP_400_BAD_REQUEST,
-                detail="Bucket does not exist",
-            )
+        return files_metadata
diff --git a/app/utils/s3_checks.py b/app/utils/s3_checks.py
index 8074a50..9ddd370 100644
--- a/app/utils/s3_checks.py
+++ b/app/utils/s3_checks.py
@@ -1,4 +1,10 @@
+import asyncio
+from typing import Set
+from urllib.parse import urlparse
+
 import boto3
+from fastapi.encoders import jsonable_encoder
+from fastapi.logger import logger
 
 from app.core.config import Settings
 
@@ -19,3 +25,27 @@ def get_s3_resource(
         raise ValueError(f"Error connecting to S3: {e}")
     else:
         return s3_resource
+
+
+async def check_file_metadata(session, file_key: str):
+
+    # get bucket and file path according to the file key
+    file_parts = urlparse(file_key)
+    bucket, obj_key = file_parts.netloc, file_parts.path.lstrip("/")
+    obj = session.ObjectSummary(bucket, obj_key)
+
+    # get the metadata
+    try:
+        metadata = {"key": file_key, "size": obj.size, "exist": True}
+    except Exception as e:
+        logger.error(f"Error getting metadata for {file_key} : {e}")
+        metadata = {"key": file_key, "size": None, "exist": False}
+    finally:
+        return jsonable_encoder(metadata)
+
+
+async def check_files_metadata(session, file_keys: Set[str]):
+    files_metadata = await asyncio.gather(
+        *[check_file_metadata(session, file_key) for file_key in file_keys]
+    )
+    return jsonable_encoder(files_metadata)