diff --git a/.gitignore b/.gitignore
index 780b818e..fc31042a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -169,3 +169,4 @@ cython_debug/
 temp
 .idea
 .python-version
+.DS_Store
diff --git a/deepset_cloud_sdk/_api/files.py b/deepset_cloud_sdk/_api/files.py
index a139454d..1efd8529 100644
--- a/deepset_cloud_sdk/_api/files.py
+++ b/deepset_cloud_sdk/_api/files.py
@@ -194,8 +194,7 @@ async def direct_upload_path(
             response = await self._deepset_cloud_api.post(
                 workspace_name,
                 "files",
-                files={"file": (file_name, file)},
-                json={"meta": meta},
+                files={"file": (file_name, file), "meta": (None, json.dumps(meta))},
                 params={"write_mode": write_mode.value},
             )
         if response.status_code != codes.CREATED or response.json().get("file_id") is None:
diff --git a/tests/integration/service/test_integration_files_service.py b/tests/integration/service/test_integration_files_service.py
index 9445b0eb..53cbaa20 100644
--- a/tests/integration/service/test_integration_files_service.py
+++ b/tests/integration/service/test_integration_files_service.py
@@ -30,6 +30,26 @@ async def test_direct_upload_path(self, integration_config: CommonConfig, worksp
             assert result.failed_upload_count == 0
             assert len(result.failed) == 0
 
+            names_of_uploaded_files = [
+                file.name
+                for file in Path("./tests/test_data/msmarco.10").glob("*.txt")
+                if not file.name.endswith(".meta.json")
+            ]
+            # Check the metadata was uploaded correctly
+            files: List[File] = []
+            async for file_batch in file_service.list_all(
+                workspace_name=workspace_name,
+                batch_size=11,
+                timeout_s=120,
+            ):
+                files += file_batch
+
+            for file in files:
+                if file.name in names_of_uploaded_files:
+                    assert (
+                        file.meta.get("source") == "msmarco"
+                    ), f"Metadata was not uploaded correctly for file '{file.name}': {file.meta}"
+
     async def test_async_upload(
         self, integration_config: CommonConfig, workspace_name: str, monkeypatch: MonkeyPatch
     ) -> None:
@@ -49,6 +69,26 @@ async def test_async_upload(
             assert result.failed_upload_count == 0
             assert len(result.failed) == 0
 
+            names_of_uploaded_files = [
+                file.name
+                for file in Path("./tests/test_data/msmarco.10").glob("*.txt")
+                if not file.name.endswith(".meta.json")
+            ]
+            # Check the metadata was uploaded correctly
+            files: List[File] = []
+            async for file_batch in file_service.list_all(
+                workspace_name=workspace_name,
+                batch_size=11,
+                timeout_s=120,
+            ):
+                files += file_batch
+
+            for file in files:
+                if file.name in names_of_uploaded_files:
+                    assert (
+                        file.meta.get("source") == "msmarco"
+                    ), f"Metadata was not uploaded correctly for file '{file.name}': {file.meta}"
+
     async def test_upload_texts(self, integration_config: CommonConfig, workspace_name: str) -> None:
         async with FilesService.factory(integration_config) as file_service:
             files = [
diff --git a/tests/test_data/msmarco.10/.DS_Store b/tests/test_data/msmarco.10/.DS_Store
deleted file mode 100644
index 6dfa2354..00000000
Binary files a/tests/test_data/msmarco.10/.DS_Store and /dev/null differ
diff --git a/tests/unit/api/test_files.py b/tests/unit/api/test_files.py
index 7f562598..5a3b8781 100644
--- a/tests/unit/api/test_files.py
+++ b/tests/unit/api/test_files.py
@@ -329,8 +329,7 @@ async def test_direct_upload_file(self, files_api: FilesAPI, mocked_deepset_clou
         mocked_deepset_cloud_api.post.assert_called_once_with(
             "test_workspace",
             "files",
-            files={"file": ("basic.txt", ANY)},
-            json={"meta": {"key": "value"}},
+            files={"file": ("basic.txt", ANY), "meta": (None, '{"key": "value"}')},
             params={
                 "write_mode": "OVERWRITE",
             },
@@ -352,8 +351,7 @@ async def test_direct_upload_file_with_name(self, files_api: FilesAPI, mocked_de
         mocked_deepset_cloud_api.post.assert_called_once_with(
             "test_workspace",
             "files",
-            files={"file": ("my_file.txt", ANY)},
-            json={"meta": {"key": "value"}},
+            files={"file": ("my_file.txt", ANY), "meta": (None, '{"key": "value"}')},
             params={"write_mode": "OVERWRITE"},
         )
 
@@ -373,8 +371,7 @@ async def test_direct_upload_with_path_as_string(self, files_api: FilesAPI, mock
         mocked_deepset_cloud_api.post.assert_called_once_with(
             "test_workspace",
             "files",
-            files={"file": ("my_file.txt", ANY)},
-            json={"meta": {"key": "value"}},
+            files={"file": ("my_file.txt", ANY), "meta": (None, '{"key": "value"}')},
             params={"write_mode": "FAIL"},
         )