diff --git a/changelogs/unreleased/22373-reduce-queries-in-api-helpers-find_project.yml b/changelogs/unreleased/22373-reduce-queries-in-api-helpers-find_project.yml
new file mode 100644
index 00000000000..7f1d40e7c21
--- /dev/null
+++ b/changelogs/unreleased/22373-reduce-queries-in-api-helpers-find_project.yml
@@ -0,0 +1,4 @@
+---
+title: 'Make API::Helpers find a project with only one query'
+merge_request: 7714
+author:
diff --git a/lib/api/groups.rb b/lib/api/groups.rb
index fc39fdf4b67..5315c22e1e4 100644
--- a/lib/api/groups.rb
+++ b/lib/api/groups.rb
@@ -82,7 +82,7 @@ module API
                         :lfs_enabled, :request_access_enabled
       end
       put ':id' do
-        group = find_group(params[:id])
+        group = find_group!(params[:id])
         authorize! :admin_group, group
 
         if ::Groups::UpdateService.new(group, current_user, declared_params(include_missing: false)).execute
@@ -96,13 +96,13 @@ module API
         success Entities::GroupDetail
       end
       get ":id" do
-        group = find_group(params[:id])
+        group = find_group!(params[:id])
         present group, with: Entities::GroupDetail
       end
 
       desc 'Remove a group.'
       delete ":id" do
-        group = find_group(params[:id])
+        group = find_group!(params[:id])
         authorize! :admin_group, group
         DestroyGroupService.new(group, current_user).execute
       end
@@ -111,7 +111,7 @@ module API
         success Entities::Project
       end
       get ":id/projects" do
-        group = find_group(params[:id])
+        group = find_group!(params[:id])
         projects = GroupProjectsFinder.new(group).execute(current_user)
         projects = paginate projects
         present projects, with: Entities::Project, user: current_user
diff --git a/lib/api/helpers.rb b/lib/api/helpers.rb
index 2c593dbb4ea..0d3ddb89dc3 100644
--- a/lib/api/helpers.rb
+++ b/lib/api/helpers.rb
@@ -68,7 +68,7 @@ module API
     end
 
     def user_project
-      @project ||= find_project(params[:id])
+      @project ||= find_project!(params[:id])
     end
 
     def available_labels
@@ -76,7 +76,15 @@ module API
     end
 
     def find_project(id)
-      project = Project.find_with_namespace(id) || Project.find_by(id: id)
+      if id =~ /^\d+$/
+        Project.find_by(id: id)
+      else
+        Project.find_with_namespace(id)
+      end
+    end
+
+    def find_project!(id)
+      project = find_project(id)
 
       if can?(current_user, :read_project, project)
         project
@@ -97,7 +105,15 @@ module API
     end
 
     def find_group(id)
-      group = Group.find_by(path: id) || Group.find_by(id: id)
+      if id =~ /^\d+$/
+        Group.find_by(id: id)
+      else
+        Group.find_by(path: id)
+      end
+    end
+
+    def find_group!(id)
+      group = find_group(id)
 
       if can?(current_user, :read_group, group)
         group
diff --git a/lib/api/helpers/members_helpers.rb b/lib/api/helpers/members_helpers.rb
index 90114f6f667..d9cae1501f8 100644
--- a/lib/api/helpers/members_helpers.rb
+++ b/lib/api/helpers/members_helpers.rb
@@ -2,7 +2,7 @@ module API
   module Helpers
     module MembersHelpers
       def find_source(source_type, id)
-        public_send("find_#{source_type}", id)
+        public_send("find_#{source_type}!", id)
       end
 
       def authorize_admin_source!(source_type, source)
diff --git a/lib/api/issues.rb b/lib/api/issues.rb
index eea5b91d4f9..2fea71870b8 100644
--- a/lib/api/issues.rb
+++ b/lib/api/issues.rb
@@ -68,7 +68,7 @@ module API
       #   GET /groups/:id/issues?milestone=1.0.0
       #   GET /groups/:id/issues?milestone=1.0.0&state=closed
       get ":id/issues" do
-        group = find_group(params[:id])
+        group = find_group!(params[:id])
 
         params[:state] ||= 'opened'
         params[:group_id] = group.id
diff --git a/lib/api/projects.rb b/lib/api/projects.rb
index ddfde178d30..2ea3c433ae2 100644
--- a/lib/api/projects.rb
+++ b/lib/api/projects.rb
@@ -379,7 +379,7 @@ module API
       #   POST /projects/:id/fork/:forked_from_id
       post ":id/fork/:forked_from_id" do
         authenticated_as_admin!
-        forked_from_project = find_project(params[:forked_from_id])
+        forked_from_project = find_project!(params[:forked_from_id])
         unless forked_from_project.nil?
           if user_project.forked_from_project.nil?
             user_project.create_forked_project_link(forked_to_project_id: user_project.id, forked_from_project_id: forked_from_project.id)
diff --git a/lib/api/services.rb b/lib/api/services.rb
index 4d23499aa39..bc427705777 100644
--- a/lib/api/services.rb
+++ b/lib/api/services.rb
@@ -65,7 +65,7 @@ module API
         detail 'Added in GitLab 8.13'
       end
       post ':id/services/:service_slug/trigger' do
-        project = Project.find_with_namespace(params[:id]) || Project.find_by(id: params[:id])
+        project = find_project(params[:id])
 
         # This is not accurate, but done to prevent leakage of the project names
         not_found!('Service') unless project
diff --git a/lib/api/triggers.rb b/lib/api/triggers.rb
index 569598fbd2c..bb4de39def1 100644
--- a/lib/api/triggers.rb
+++ b/lib/api/triggers.rb
@@ -13,7 +13,7 @@ module API
         optional :variables, type: Hash, desc: 'The list of variables to be injected into build'
       end
       post ":id/(ref/:ref/)trigger/builds" do
-        project = Project.find_with_namespace(params[:id]) || Project.find_by(id: params[:id])
+        project = find_project(params[:id])
         trigger = Ci::Trigger.find_by_token(params[:token].to_s)
         not_found! unless project && trigger
         unauthorized! unless trigger.project == project