diff --git a/CHANGES.md b/CHANGES.md
index d72b9749d..4fa952b35 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -4,7 +4,9 @@
 
 ### Added
 
+* Add ability to override ItemCollectionUri and SearchGetRequest models ([#271](https://github.com/stac-utils/stac-fastapi/pull/271))
 * Added `collections` attribute to list of default fields to include, so that we satisfy the STAC API spec, which requires a `collections` attribute to be output when an item is part of a collection
+
 ### Removed
 
 ### Changed
diff --git a/stac_fastapi/api/stac_fastapi/api/app.py b/stac_fastapi/api/stac_fastapi/api/app.py
index d2966314a..cabc0f451 100644
--- a/stac_fastapi/api/stac_fastapi/api/app.py
+++ b/stac_fastapi/api/stac_fastapi/api/app.py
@@ -73,6 +73,8 @@ class StacApi:
     stac_version: str = attr.ib(default=STAC_VERSION)
     description: str = attr.ib(default="stac-fastapi")
     search_request_model: Type[Search] = attr.ib(default=STACSearch)
+    search_get_request: Type[SearchGetRequest] = attr.ib(default=SearchGetRequest)
+    item_collection_uri: Type[ItemCollectionUri] = attr.ib(default=ItemCollectionUri)
     response_class: Type[Response] = attr.ib(default=JSONResponse)
     middlewares: List = attr.ib(default=attr.Factory(lambda: [BrotliMiddleware]))
 
@@ -199,7 +201,9 @@ def register_get_search(self):
             response_model_exclude_unset=True,
             response_model_exclude_none=True,
             methods=["GET"],
-            endpoint=self._create_endpoint(self.client.get_search, SearchGetRequest),
+            endpoint=self._create_endpoint(
+                self.client.get_search, self.search_get_request
+            ),
         )
 
     def register_get_collections(self):
@@ -255,7 +259,7 @@ def register_get_item_collection(self):
             response_model_exclude_none=True,
             methods=["GET"],
             endpoint=self._create_endpoint(
-                self.client.item_collection, ItemCollectionUri
+                self.client.item_collection, self.item_collection_uri
             ),
         )
 
diff --git a/stac_fastapi/pgstac/stac_fastapi/pgstac/core.py b/stac_fastapi/pgstac/stac_fastapi/pgstac/core.py
index 68719c035..b1d001025 100644
--- a/stac_fastapi/pgstac/stac_fastapi/pgstac/core.py
+++ b/stac_fastapi/pgstac/stac_fastapi/pgstac/core.py
@@ -1,7 +1,7 @@
 """Item crud client."""
 import re
 from datetime import datetime
-from typing import Any, Dict, List, Optional, Union
+from typing import Any, Dict, List, Optional, Type, Union
 from urllib.parse import urljoin
 
 import attr
@@ -27,6 +27,8 @@
 class CoreCrudClient(AsyncBaseCoreClient):
     """Client for core endpoints defined by stac."""
 
+    search_request_model: Type[PgstacSearch] = attr.ib(init=False, default=PgstacSearch)
+
     async def all_collections(self, **kwargs) -> Collections:
         """Read all collections from the database."""
         request: Request = kwargs["request"]
@@ -168,7 +170,7 @@ async def _search_base(
         return collection
 
     async def item_collection(
-        self, id: str, limit: int = 10, token: str = None, **kwargs
+        self, id: str, limit: Optional[int] = None, token: str = None, **kwargs
     ) -> ItemCollection:
         """Get all items from a specific collection.
 
@@ -185,7 +187,7 @@ async def item_collection(
         # If collection does not exist, NotFoundError wil be raised
         await self.get_collection(id, **kwargs)
 
-        req = PgstacSearch(collections=[id], limit=limit, token=token)
+        req = self.search_request_model(collections=[id], limit=limit, token=token)
         item_collection = await self._search_base(req, **kwargs)
         links = await CollectionLinks(
             collection_id=id, request=kwargs["request"]
@@ -207,7 +209,9 @@ async def get_item(self, item_id: str, collection_id: str, **kwargs) -> Item:
         # If collection does not exist, NotFoundError wil be raised
         await self.get_collection(collection_id, **kwargs)
 
-        req = PgstacSearch(ids=[item_id], collections=[collection_id], limit=1)
+        req = self.search_request_model(
+            ids=[item_id], collections=[collection_id], limit=1
+        )
         item_collection = await self._search_base(req, **kwargs)
         if not item_collection["features"]:
             raise NotFoundError(
@@ -238,7 +242,7 @@ async def get_search(
         ids: Optional[List[str]] = None,
         bbox: Optional[List[NumType]] = None,
         datetime: Optional[Union[str, datetime]] = None,
-        limit: Optional[int] = 10,
+        limit: Optional[int] = None,
         query: Optional[str] = None,
         token: Optional[str] = None,
         fields: Optional[List[str]] = None,
@@ -292,7 +296,7 @@ async def get_search(
 
         # Do the request
         try:
-            search_request = PgstacSearch(**base_args)
+            search_request = self.search_request_model(**base_args)
         except ValidationError:
             raise HTTPException(status_code=400, detail="Invalid parameters provided")
         return await self.post_search(search_request, request=kwargs["request"])