diff --git a/changelog/325.removed.md b/changelog/325.removed.md
new file mode 100644
index 000000000..e79b0c1d4
--- /dev/null
+++ b/changelog/325.removed.md
@@ -0,0 +1 @@
+Removed `client.branch.diff_data()` from both the async and sync clients. The method relied on a `GET /api/diff/data` REST endpoint that does not exist in Infrahub, so every call returned a 404. Use `client.get_diff_tree()` to retrieve the full diff of a branch against its base branch, or `client.get_diff_summary()` for the list of changed nodes; both use the `DiffTree` GraphQL query.
diff --git a/docs/docs/python-sdk/guides/branches.mdx b/docs/docs/python-sdk/guides/branches.mdx
index 64016048e..ffe2049d7 100644
--- a/docs/docs/python-sdk/guides/branches.mdx
+++ b/docs/docs/python-sdk/guides/branches.mdx
@@ -108,15 +108,40 @@ The Python SDK provides multiple methods to manage the branches in an Infrahub i
   </TabItem>
 </Tabs>
 
-## Generating a diff for a branch
+## Getting the diff for a branch
+
+Use `get_diff_tree` to retrieve the full diff of a branch compared to its base branch, including summary counts and the list of changed nodes. It returns `None` if no diff exists for the branch.
+
+<Tabs groupId="async-sync">
+  <TabItem value="Async" default>
+
+  ```python
+  from infrahub_sdk import InfrahubClient
+  client = InfrahubClient()
+  diff = await client.get_diff_tree(branch="new-branch")
+  ```
+
+  </TabItem>
+  <TabItem value="Sync" default>
+
+  ```python
+  from infrahub_sdk import InfrahubClientSync
+  client = InfrahubClientSync()
+  diff = client.get_diff_tree(branch="new-branch")
+  ```
+
+  </TabItem>
+</Tabs>
+
+If you only need the list of changed nodes, `get_diff_summary` returns them without the diff metadata.
 
 <Tabs groupId="async-sync">
   <TabItem value="Async" default>
 
   ```python
   from infrahub_sdk import InfrahubClient
-  client = await InfrahubClient()
-  diff = await client.branch.diff_data(branch_name="new-branch")
+  client = InfrahubClient()
+  node_diffs = await client.get_diff_summary(branch="new-branch")
   ```
 
   </TabItem>
@@ -125,7 +150,7 @@ The Python SDK provides multiple methods to manage the branches in an Infrahub i
   ```python
   from infrahub_sdk import InfrahubClientSync
   client = InfrahubClientSync()
-  diff = client.branch.diff_data(branch_name="new-branch")
+  node_diffs = client.get_diff_summary(branch="new-branch")
   ```
 
   </TabItem>
diff --git a/infrahub_sdk/branch.py b/infrahub_sdk/branch.py
index 5e1459a6d..b310522e4 100644
--- a/infrahub_sdk/branch.py
+++ b/infrahub_sdk/branch.py
@@ -1,14 +1,12 @@
 from __future__ import annotations
 
 from enum import Enum
-from typing import TYPE_CHECKING, Any, Literal, overload
-from urllib.parse import urlencode
+from typing import TYPE_CHECKING, Literal, overload
 
 from pydantic import BaseModel
 
 from .exceptions import BranchNotFoundError
 from .graphql import Mutation, Query
-from .utils import decode_json
 
 if TYPE_CHECKING:
     from .client import InfrahubClient, InfrahubClientSync
@@ -61,30 +59,7 @@ class BranchData(BaseModel):
 QUERY_ONE_BRANCH_DATA = {"Branch": {**BRANCH_DATA, **BRANCH_DATA_FILTER}}
 
 
-class InfraHubBranchManagerBase:
-    @classmethod
-    def generate_diff_data_url(
-        cls,
-        client: InfrahubClient | InfrahubClientSync,
-        branch_name: str,
-        branch_only: bool = True,
-        time_from: str | None = None,
-        time_to: str | None = None,
-    ) -> str:
-        """Generate the URL for the diff_data function."""
-        url = f"{client.address}/api/diff/data"
-        url_params = {}
-        url_params["branch"] = branch_name
-        url_params["branch_only"] = str(branch_only).lower()
-        if time_from:
-            url_params["time_from"] = time_from
-        if time_to:
-            url_params["time_to"] = time_to
-
-        return url + urlencode(url_params)
-
-
-class InfrahubBranchManager(InfraHubBranchManagerBase):
+class InfrahubBranchManager:
     def __init__(self, client: InfrahubClient) -> None:
         self.client = client
 
@@ -206,25 +181,8 @@ async def get(self, branch_name: str) -> BranchData:
             raise BranchNotFoundError(identifier=branch_name)
         return BranchData(**data["Branch"][0])
 
-    async def diff_data(
-        self,
-        branch_name: str,
-        branch_only: bool = True,
-        time_from: str | None = None,
-        time_to: str | None = None,
-    ) -> dict[Any, Any]:
-        url = self.generate_diff_data_url(
-            client=self.client,
-            branch_name=branch_name,
-            branch_only=branch_only,
-            time_from=time_from,
-            time_to=time_to,
-        )
-        response = await self.client._get(url=url, headers=self.client.headers)
-        return decode_json(response=response)
-
 
-class InfrahubBranchManagerSync(InfraHubBranchManagerBase):
+class InfrahubBranchManagerSync:
     def __init__(self, client: InfrahubClientSync) -> None:
         self.client = client
 
@@ -300,23 +258,6 @@ def delete(self, branch_name: str) -> bool:
         response = self.client.execute_graphql(query=query.render(), tracker="mutation-branch-delete")
         return response["BranchDelete"]["ok"]
 
-    def diff_data(
-        self,
-        branch_name: str,
-        branch_only: bool = True,
-        time_from: str | None = None,
-        time_to: str | None = None,
-    ) -> dict[Any, Any]:
-        url = self.generate_diff_data_url(
-            client=self.client,
-            branch_name=branch_name,
-            branch_only=branch_only,
-            time_from=time_from,
-            time_to=time_to,
-        )
-        response = self.client._get(url=url, headers=self.client.headers)
-        return decode_json(response=response)
-
     def merge(self, branch_name: str) -> bool:
         input_data = {
             "data": {