diff --git a/src/types.ts b/src/types.ts
index 84e17e1f..f641d4ed 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2018 StApps
+ * Copyright (C) 2018, 2019 StApps
  * This program is free software: you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
  * Software Foundation, version 3.
@@ -12,6 +12,65 @@
  * You should have received a copy of the GNU General Public License along with
  * this program. If not, see <https://www.gnu.org/licenses/>.
  */
+
+/**
+ * Scope of membership
+ */
+export enum MembershipScope {
+  GROUPS = 'groups',
+  PROJECTS = 'projects',
+}
+
+/**
+ * Scope
+ */
+export enum Scope {
+  ISSUES = 'issues',
+  MERGE_REQUESTS = 'merge_requests',
+}
+
+/**
+ * Merge request state
+ */
+export enum MergeRequestState {
+  CLOSED = 'closed',
+  LOCKED = 'locked',
+  MERGED = 'merged',
+  OPENED = 'opened',
+}
+
+/**
+ * Issue state
+ */
+export enum IssueState {
+  CLOSED = 'closed',
+  OPENED = 'opened',
+  REOPENED = 'reopened',
+}
+
+/**
+ * Milestone state
+ */
+export enum MilestoneState {
+  ACTIVE = 'active',
+  CLOSED = 'closed',
+}
+
+/**
+ * User state
+ */
+export enum UserState {
+  ACTIVE = 'active',
+  BLOCKED = 'blocked',
+}
+
+/**
+ * Merge request merge status
+ */
+export enum MergeRequestMergeStatus {
+  CAN_BE_MERGED = 'can_be_merged',
+}
+
 /**
  * GitLab label
  */
@@ -138,7 +197,7 @@ export interface Milestone {
   iid: number;
   project_id: number;
   start_date: string;
-  state: string;
+  state: MilestoneState;
   title: string;
   updated_at: string;
 }
@@ -162,7 +221,7 @@ export interface User {
   avatar_url: string;
   id: number;
   name: string;
-  state: string;
+  state: UserState;
   username: string;
   web_url: string;
 }
@@ -186,7 +245,7 @@ export interface Issue extends ThingWithTimeStats {
   labels: string[];
   milestone: Milestone | null;
   project_id: number;
-  state: string;
+  state: IssueState;
   title: string;
   updated_at: string;
   upvotes: number;
@@ -209,7 +268,7 @@ export interface MergeRequest extends ThingWithTimeStats {
   iid: number;
   labels: Label[];
   merge_commit_sha: string;
-  merge_status: string;
+  merge_status: MergeRequestMergeStatus;
   merge_when_pipeline_succeeds: boolean;
   milestone: Milestone;
   project_id: number;
@@ -217,7 +276,7 @@ export interface MergeRequest extends ThingWithTimeStats {
   should_remove_source_branch: boolean;
   source_branch: string;
   source_project_id: number;
-  state: string;
+  state: MergeRequestState;
   target_branch: string;
   target_project_id: number;
   title: string;