diff --git a/keystone/api/projects.py b/keystone/api/projects.py
index cd5d73cbc1..31b8767091 100644
--- a/keystone/api/projects.py
+++ b/keystone/api/projects.py
@@ -17,10 +17,11 @@ import http.client
 
 import flask
 
+from keystone.api import validation
 from keystone.common import json_home
 from keystone.common import provider_api
 from keystone.common import rbac_enforcer
-from keystone.common import validation
+from keystone.common import validation as ks_validation
 import keystone.conf
 from keystone import exception
 from keystone.i18n import _
@@ -54,6 +55,7 @@ class ProjectResource(ks_flask.ResourceBase):
     )
 
     def _expand_project_ref(self, ref):
+        # NOTE(gtema): This functionality is not described in the API-Ref
         parents_as_list = self.query_filter_is_true('parents_as_list')
         parents_as_ids = self.query_filter_is_true('parents_as_ids')
 
@@ -100,7 +102,9 @@ class ProjectResource(ks_flask.ResourceBase):
                 )
             )
 
-    def _get_project(self, project_id):
+    @validation.request_body_schema(None)
+    @validation.response_body_schema(schema.project_get_response_body)
+    def get(self, project_id: str):
         """Get project.
 
         GET/HEAD /v3/projects/{project_id}
@@ -113,7 +117,51 @@ class ProjectResource(ks_flask.ResourceBase):
         self._expand_project_ref(project)
         return self.wrap_member(project)
 
-    def _list_projects(self):
+    @validation.request_body_schema(schema.project_update_request_body)
+    @validation.response_body_schema(schema.project_update_response_body)
+    def patch(self, project_id):
+        """Update project.
+
+        PATCH /v3/projects/{project_id}
+        """
+        ENFORCER.enforce_call(
+            action='identity:update_project',
+            build_target=_build_project_target_enforcement,
+        )
+        project = self.request_body_json.get('project', {})
+        self._require_matching_id(project)
+        ref = PROVIDERS.resource_api.update_project(
+            project_id, project, initiator=self.audit_initiator
+        )
+        return self.wrap_member(ref)
+
+    @validation.request_body_schema(None)
+    @validation.response_body_schema(None)
+    def delete(self, project_id):
+        """Delete project.
+
+        DELETE /v3/projects/{project_id}
+        """
+        ENFORCER.enforce_call(
+            action='identity:delete_project',
+            build_target=_build_project_target_enforcement,
+        )
+        PROVIDERS.resource_api.delete_project(
+            project_id, initiator=self.audit_initiator
+        )
+        return None, http.client.NO_CONTENT
+
+
+class ProjectsResource(ks_flask.ResourceBase):
+    collection_key = 'projects'
+    member_key = 'project'
+    get_member_from_driver = PROVIDERS.deferred_provider_lookup(
+        api='resource_api', method='get_project'
+    )
+
+    @validation.request_query_schema(schema.project_index_request_query)
+    @validation.response_body_schema(schema.project_index_response_body)
+    def get(self):
         """List projects.
 
         GET/HEAD /v3/projects
@@ -148,17 +196,8 @@ class ProjectResource(ks_flask.ResourceBase):
             filtered_refs = refs
         return self.wrap_collection(filtered_refs, hints=hints)
 
-    def get(self, project_id=None):
-        """Get project or list projects.
-
-        GET/HEAD /v3/projects
-        GET/HEAD /v3/projects/{project_id}
-        """
-        if project_id is not None:
-            return self._get_project(project_id)
-        else:
-            return self._list_projects()
-
+    @validation.request_body_schema(schema.project_create_request_body)
+    @validation.response_body_schema(schema.project_create_response_body)
     def post(self):
         """Create project.
 
@@ -169,7 +208,6 @@ class ProjectResource(ks_flask.ResourceBase):
         ENFORCER.enforce_call(
             action='identity:create_project', target_attr=target
         )
-        validation.lazy_validate(schema.project_create, project)
         project = self._assign_unique_id(project)
         if not project.get('is_domain'):
             project = self._normalize_domain_id(project)
@@ -187,37 +225,6 @@ class ProjectResource(ks_flask.ResourceBase):
             raise exception.ValidationError(e)
         return self.wrap_member(ref), http.client.CREATED
 
-    def patch(self, project_id):
-        """Update project.
-
-        PATCH /v3/projects/{project_id}
-        """
-        ENFORCER.enforce_call(
-            action='identity:update_project',
-            build_target=_build_project_target_enforcement,
-        )
-        project = self.request_body_json.get('project', {})
-        validation.lazy_validate(schema.project_update, project)
-        self._require_matching_id(project)
-        ref = PROVIDERS.resource_api.update_project(
-            project_id, project, initiator=self.audit_initiator
-        )
-        return self.wrap_member(ref)
-
-    def delete(self, project_id):
-        """Delete project.
-
-        DELETE /v3/projects/{project_id}
-        """
-        ENFORCER.enforce_call(
-            action='identity:delete_project',
-            build_target=_build_project_target_enforcement,
-        )
-        PROVIDERS.resource_api.delete_project(
-            project_id, initiator=self.audit_initiator
-        )
-        return None, http.client.NO_CONTENT
-
 
 class _ProjectTagResourceBase(ks_flask.ResourceBase):
     collection_key = 'projects'
@@ -237,6 +244,8 @@ class _ProjectTagResourceBase(ks_flask.ResourceBase):
 
 
 class ProjectTagsResource(_ProjectTagResourceBase):
+    @validation.request_body_schema(None)
+    @validation.response_body_schema(schema.tags_response_body)
     def get(self, project_id):
         """List tags associated with a given project.
 
@@ -249,6 +258,8 @@ class ProjectTagsResource(_ProjectTagResourceBase):
         ref = PROVIDERS.resource_api.list_project_tags(project_id)
         return self.wrap_member(ref)
 
+    @validation.request_body_schema(schema.tags_update_request_body)
+    @validation.response_body_schema(schema.tags_response_body)
     def put(self, project_id):
         """Update all tags associated with a given project.
 
@@ -259,12 +270,14 @@ class ProjectTagsResource(_ProjectTagResourceBase):
             build_target=_build_project_target_enforcement,
         )
         tags = self.request_body_json.get('tags', {})
-        validation.lazy_validate(schema.project_tags_update, tags)
+        ks_validation.lazy_validate(schema.project_tags_update, tags)
         ref = PROVIDERS.resource_api.update_project_tags(
             project_id, tags, initiator=self.audit_initiator
         )
         return self.wrap_member(ref)
 
+    @validation.request_body_schema(None)
+    @validation.response_body_schema(None)
     def delete(self, project_id):
         """Delete all tags associated with a given project.
 
@@ -279,6 +292,8 @@ class ProjectTagsResource(_ProjectTagResourceBase):
 
 
 class ProjectTagResource(_ProjectTagResourceBase):
+    @validation.request_body_schema(None)
+    @validation.response_body_schema(None)
     def get(self, project_id, value):
         """Get information for a single tag associated with a given project.
 
@@ -291,6 +306,8 @@ class ProjectTagResource(_ProjectTagResourceBase):
         PROVIDERS.resource_api.get_project_tag(project_id, value)
         return None, http.client.NO_CONTENT
 
+    @validation.request_body_schema(None)
+    @validation.response_body_schema(None)
     def put(self, project_id, value):
         """Add a single tag to a project.
 
@@ -300,11 +317,11 @@ class ProjectTagResource(_ProjectTagResourceBase):
             action='identity:create_project_tag',
             build_target=_build_project_target_enforcement,
         )
-        validation.lazy_validate(schema.project_tag_create, value)
+        ks_validation.lazy_validate(schema.project_tag_create, value)
         # Check if we will exceed the max number of tags on this project
         tags = PROVIDERS.resource_api.list_project_tags(project_id)
         tags.append(value)
-        validation.lazy_validate(schema.project_tags_update, tags)
+        ks_validation.lazy_validate(schema.project_tags_update, tags)
         PROVIDERS.resource_api.create_project_tag(
             project_id, value, initiator=self.audit_initiator
         )
@@ -313,6 +330,8 @@ class ProjectTagResource(_ProjectTagResourceBase):
         response.headers['Location'] = url
         return response
 
+    @validation.request_body_schema(None)
+    @validation.response_body_schema(None)
     def delete(self, project_id, value):
         """Delete a single tag from a project.
 
@@ -566,8 +585,21 @@ class ProjectGroupListGrantResource(_ProjectGrantResourceBase):
 class ProjectAPI(ks_flask.APIBase):
     _name = 'projects'
     _import_name = __name__
-    resources = [ProjectResource]
     resource_mapping = [
+        ks_flask.construct_resource_map(
+            resource=ProjectsResource,
+            url='/projects',
+            resource_kwargs={},
+            rel="projects",
+            path_vars=None,
+        ),
+        ks_flask.construct_resource_map(
+            resource=ProjectResource,
+            url='/projects/<string:project_id>',
+            resource_kwargs={},
+            rel="project",
+            path_vars={'project_id': json_home.Parameters.PROJECT_ID},
+        ),
         ks_flask.construct_resource_map(
             resource=ProjectTagsResource,
             url='/projects/<string:project_id>/tags',
diff --git a/keystone/api/validation/parameter_types.py b/keystone/api/validation/parameter_types.py
index df0c270979..5da1c6448a 100644
--- a/keystone/api/validation/parameter_types.py
+++ b/keystone/api/validation/parameter_types.py
@@ -13,6 +13,8 @@
 """Common parameter types for validating API requests."""
 from typing import Any
 
+empty: dict[str, Any] = {"type": "null"}
+
 name: dict[str, Any] = {
     "type": "string",
     "minLength": 1,
diff --git a/keystone/api/validation/response_types.py b/keystone/api/validation/response_types.py
index 243a3634c6..6732f8895d 100644
--- a/keystone/api/validation/response_types.py
+++ b/keystone/api/validation/response_types.py
@@ -39,3 +39,12 @@ truncated: dict[str, Any] = {
         "response limit"
     ),
 }
+
+tags: dict[str, Any] = {
+    "type": "object",
+    "properties": {
+        "tags": {"type": "array", "items": {"type": "string"}},
+        "links": links,
+    },
+    "additionalProperties": False,
+}
diff --git a/keystone/resource/schema.py b/keystone/resource/schema.py
index 687d75f027..b3480dd6aa 100644
--- a/keystone/resource/schema.py
+++ b/keystone/resource/schema.py
@@ -9,9 +9,12 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
+from typing import Any
 
+from keystone.api.validation import parameter_types
+from keystone.api.validation import response_types
 from keystone.common import validation
-from keystone.common.validation import parameter_types
+from keystone.common.validation import parameter_types as old_parameter_types
 from keystone.resource.backends import resource_options as ro
 
 _name_properties = {
@@ -41,12 +44,12 @@ _project_tags_list_properties = {
 }
 
 _project_properties = {
-    'description': validation.nullable(parameter_types.description),
+    'description': validation.nullable(old_parameter_types.description),
     # NOTE(htruta): domain_id is nullable for projects acting as a domain.
-    'domain_id': validation.nullable(parameter_types.id_string),
+    'domain_id': validation.nullable(old_parameter_types.id_string),
     'enabled': parameter_types.boolean,
     'is_domain': parameter_types.boolean,
-    'parent_id': validation.nullable(parameter_types.id_string),
+    'parent_id': validation.nullable(old_parameter_types.id_string),
     'name': _name_properties,
     'tags': _project_tags_list_properties,
     'options': ro.PROJECT_OPTIONS_REGISTRY.json_schema,
@@ -77,7 +80,7 @@ project_update = {
 }
 
 _domain_properties = {
-    'description': validation.nullable(parameter_types.description),
+    'description': validation.nullable(old_parameter_types.description),
     'enabled': parameter_types.boolean,
     'name': _name_properties,
     'tags': project_tags_update,
@@ -99,3 +102,91 @@ domain_update = {
     'minProperties': 1,
     'additionalProperties': True,
 }
+
+project_index_request_query = {
+    'type': 'object',
+    'properties': {
+        "domain_id": parameter_types.domain_id,
+        "enabled": parameter_types.boolean,
+        "name": _name_properties,
+        "parent_id": parameter_types.parent_id,
+        "is_domain": parameter_types.boolean,
+        "tags": parameter_types.tags,
+        "tags-any": parameter_types.tags,
+        "not-tags": parameter_types.tags,
+        "not-tags-any": parameter_types.tags,
+    },
+}
+
+project_schema: dict[str, Any] = {
+    "type": "object",
+    "properties": {
+        "id": {"type": "string", "readOnly": True},
+        "links": response_types.resource_links,
+        **_project_properties,
+    },
+    "additionalProperties": True,
+}
+
+project_get_response_body: dict[str, Any] = {
+    "type": "object",
+    "properties": {"project": project_schema},
+    "additionalProperties": False,
+}
+
+project_index_response_body: dict[str, Any] = {
+    "type": "object",
+    "properties": {
+        "projects": {"type": "array", "items": project_schema},
+        "links": response_types.links,
+        "truncated": response_types.truncated,
+    },
+    "additionalProperties": False,
+}
+
+project_create_request_body: dict[str, Any] = {
+    "type": "object",
+    "properties": {
+        "project": {
+            "type": "object",
+            "properties": _project_properties,
+            "required": ["name"],
+        }
+    },
+    "additionalProperties": False,
+}
+
+project_create_response_body: dict[str, Any] = project_get_response_body
+
+# Explicitly list attributes allowed to be updated.
+# Since updating `domain_id` is since very long time marked deprecated do not
+# even include it in the schema
+project_update_request_body: dict[str, Any] = {
+    "type": "object",
+    "properties": {
+        "project": {
+            "type": "object",
+            "properties": {
+                'description': validation.nullable(
+                    old_parameter_types.description
+                ),
+                'enabled': parameter_types.boolean,
+                'name': _name_properties,
+                'tags': _project_tags_list_properties,
+            },
+        }
+    },
+    "additionalProperties": False,
+}
+
+project_update_response_body: dict[str, Any] = project_get_response_body
+
+tags_response_body: dict[str, Any] = response_types.tags
+
+tags_update_request_body: dict[str, Any] = {
+    "type": "object",
+    "properties": {
+        "tags": {"type": "array", "items": _project_tag_name_properties}
+    },
+    "additionalProperties": False,
+}
diff --git a/keystone/tests/unit/test_validation.py b/keystone/tests/unit/test_validation.py
index a735f2864a..6e9d0fb7b8 100644
--- a/keystone/tests/unit/test_validation.py
+++ b/keystone/tests/unit/test_validation.py
@@ -82,7 +82,12 @@ entity_update = {
 
 _VALID_ENABLED_FORMATS = [True, False]
 
-_INVALID_ENABLED_FORMATS = ['some string', 1, 0, 'True', 'False']
+# NOTE(gtema): During impliementing JsonSchema validation some
+# normalization has been done and it was noticed that value 'True' for boolean
+# is explicitly expected in i.e. is_domain while other test verifies it is
+# rejected. Therefore `True` and `False` values are removed from invalid values
+# to be more conforming to other OpenStack services.
+_INVALID_ENABLED_FORMATS = ['some string', 1, 0]
 
 _INVALID_DESC_FORMATS = [False, 1, 2.0]