diff --git a/app/actions/server.js b/app/actions/server.js
deleted file mode 100644
index acc7c7cb..00000000
--- a/app/actions/server.js
+++ /dev/null
@@ -1,61 +0,0 @@
-import { SERVER } from './actionsTypes';
-
-export function selectServerRequest(server, version, fetchVersion = true, changeServer = false) {
-	return {
-		type: SERVER.SELECT_REQUEST,
-		server,
-		version,
-		fetchVersion,
-		changeServer
-	};
-}
-
-export function selectServerSuccess(server, version) {
-	return {
-		type: SERVER.SELECT_SUCCESS,
-		server,
-		version
-	};
-}
-
-export function selectServerFailure() {
-	return {
-		type: SERVER.SELECT_FAILURE
-	};
-}
-
-// TODO
-export function serverRequest(server, username, fromServerHistory = false) {
-	return {
-		type: SERVER.REQUEST,
-		server,
-		username: username || null,
-		fromServerHistory
-	};
-}
-
-export function serverSuccess() {
-	return {
-		type: SERVER.SUCCESS
-	};
-}
-
-export function serverFailure(err) {
-	return {
-		type: SERVER.FAILURE,
-		err
-	};
-}
-
-export function serverInitAdd(previousServer) {
-	return {
-		type: SERVER.INIT_ADD,
-		previousServer
-	};
-}
-
-export function serverFinishAdd() {
-	return {
-		type: SERVER.FINISH_ADD
-	};
-}
diff --git a/app/actions/server.ts b/app/actions/server.ts
new file mode 100644
index 00000000..da8ee6d4
--- /dev/null
+++ b/app/actions/server.ts
@@ -0,0 +1,90 @@
+import { Action } from 'redux';
+
+import { SERVER } from './actionsTypes';
+
+interface ISelectServer extends Action {
+	server: string;
+	version?: string;
+	fetchVersion: boolean;
+	changeServer: boolean;
+}
+
+interface ISelectServerSuccess extends Action {
+	server: string;
+	version: string;
+}
+
+interface IServer extends Action {
+	server: string;
+	username: string | null;
+	fromServerHistory: boolean;
+}
+
+interface IServerInit extends Action {
+	previousServer: string;
+}
+
+interface IServerFailure extends Action {
+	err: any;
+}
+
+export type TActionServer = ISelectServer & ISelectServerSuccess & IServer & IServerInit & IServerFailure;
+
+export function selectServerRequest(server: string, version?: string, fetchVersion = true, changeServer = false): ISelectServer {
+	return {
+		type: SERVER.SELECT_REQUEST,
+		server,
+		version,
+		fetchVersion,
+		changeServer
+	};
+}
+
+export function selectServerSuccess(server: string, version: string): ISelectServerSuccess {
+	return {
+		type: SERVER.SELECT_SUCCESS,
+		server,
+		version
+	};
+}
+
+export function selectServerFailure(): Action {
+	return {
+		type: SERVER.SELECT_FAILURE
+	};
+}
+
+export function serverRequest(server: string, username: string | null = null, fromServerHistory = false): IServer {
+	return {
+		type: SERVER.REQUEST,
+		server,
+		username,
+		fromServerHistory
+	};
+}
+
+export function serverSuccess(): Action {
+	return {
+		type: SERVER.SUCCESS
+	};
+}
+
+export function serverFailure(err: any): IServerFailure {
+	return {
+		type: SERVER.FAILURE,
+		err
+	};
+}
+
+export function serverInitAdd(previousServer: string): IServerInit {
+	return {
+		type: SERVER.INIT_ADD,
+		previousServer
+	};
+}
+
+export function serverFinishAdd(): Action {
+	return {
+		type: SERVER.FINISH_ADD
+	};
+}
diff --git a/app/definitions/redux/index.ts b/app/definitions/redux/index.ts
index 3a46d6ef..2154bdfc 100644
--- a/app/definitions/redux/index.ts
+++ b/app/definitions/redux/index.ts
@@ -1,3 +1,5 @@
+// ACTIONS
+import { TActionServer } from '../../actions/server';
 import { TActionActiveUsers } from '../../actions/activeUsers';
 import { TActionCustomEmojis } from '../../actions/customEmojis';
 import { TActionEncryption } from '../../actions/encryption';
@@ -13,6 +15,7 @@ import { IEncryption } from '../../reducers/encryption';
 import { IInviteLinks } from '../../reducers/inviteLinks';
 import { IRoles } from '../../reducers/roles';
 import { ISelectedUsers } from '../../reducers/selectedUsers';
+import { IServer } from '../../reducers/server';
 import { IConnect } from '../../reducers/connect';
 import { ISettings } from '../../reducers/settings';
 
@@ -20,7 +23,7 @@ export interface IApplicationState {
 	settings: ISettings;
 	login: any;
 	meteor: IConnect;
-	server: any;
+	server: IServer;
 	selectedUsers: ISelectedUsers;
 	createChannel: any;
 	app: any;
@@ -48,4 +51,5 @@ export type TApplicationActions = TActionActiveUsers &
 	IActionSettings &
 	TActionEncryption &
 	TActionSortPreferences &
-	TActionUserTyping;
+	TActionUserTyping &
+	TActionServer;
diff --git a/app/reducers/server.test.ts b/app/reducers/server.test.ts
new file mode 100644
index 00000000..0b0f8fd4
--- /dev/null
+++ b/app/reducers/server.test.ts
@@ -0,0 +1,68 @@
+import {
+	selectServerRequest,
+	serverRequest,
+	selectServerSuccess,
+	serverInitAdd,
+	serverFailure,
+	serverFinishAdd,
+	selectServerFailure
+} from '../actions/server';
+import { mockedStore } from './mockedStore';
+import { initialState } from './server';
+
+describe('test server reducer', () => {
+	it('should return initial state', () => {
+		const state = mockedStore.getState().server;
+		expect(state).toEqual(initialState);
+	});
+
+	it('should return modified store after serverRequest', () => {
+		const server = 'https://open.rocket.chat/';
+		mockedStore.dispatch(serverRequest(server));
+		const state = mockedStore.getState().server;
+		const manipulated = { ...initialState, connecting: true, failure: false };
+		expect(state).toEqual(manipulated);
+	});
+
+	it('should return modified store after selectServerFailure', () => {
+		mockedStore.dispatch(selectServerFailure());
+		const state = mockedStore.getState().server;
+		const manipulated = { ...initialState, connecting: false, connected: false, loading: false, changingServer: false };
+		expect(state).toEqual(manipulated);
+	});
+
+	it('should return modified store after selectServer', () => {
+		const server = 'https://open.rocket.chat/';
+		mockedStore.dispatch(selectServerRequest(server));
+		const state = mockedStore.getState().server.server;
+		expect(state).toEqual(server);
+	});
+
+	it('should return modified store after selectServerSucess', () => {
+		const server = 'https://open.rocket.chat/';
+		const version = '4.1.0';
+		mockedStore.dispatch(selectServerSuccess(server, version));
+		const state = mockedStore.getState().server;
+		const manipulated = { ...initialState, server, version, connected: true, loading: false };
+		expect(state).toEqual(manipulated);
+	});
+
+	it('should return modified store after serverRequestInitAdd', () => {
+		const previousServer = 'https://mobile.rocket.chat';
+		mockedStore.dispatch(serverInitAdd(previousServer));
+		const state = mockedStore.getState().server.previousServer;
+		expect(state).toEqual(previousServer);
+	});
+
+	it('should return modified store after serverFinishAdd', () => {
+		mockedStore.dispatch(serverFinishAdd());
+		const state = mockedStore.getState().server.previousServer;
+		expect(state).toEqual(null);
+	});
+
+	it('should return modified store after serverRequestFailure', () => {
+		mockedStore.dispatch(serverFailure('error'));
+		const state = mockedStore.getState().server;
+		expect(state.failure).toEqual(true);
+	});
+});
diff --git a/app/reducers/server.js b/app/reducers/server.ts
similarity index 76%
rename from app/reducers/server.js
rename to app/reducers/server.ts
index 14c7bbfd..02a7ffed 100644
--- a/app/reducers/server.js
+++ b/app/reducers/server.ts
@@ -1,6 +1,18 @@
+import { TActionServer } from '../actions/server';
 import { SERVER } from '../actions/actionsTypes';
 
-const initialState = {
+export interface IServer {
+	connecting: boolean;
+	connected: boolean;
+	failure: boolean;
+	server: string;
+	version: string | null;
+	loading: boolean;
+	previousServer: string | null;
+	changingServer: boolean;
+}
+
+export const initialState: IServer = {
 	connecting: false,
 	connected: false,
 	failure: false,
@@ -11,7 +23,7 @@ const initialState = {
 	changingServer: false
 };
 
-export default function server(state = initialState, action) {
+export default function server(state = initialState, action: TActionServer): IServer {
 	switch (action.type) {
 		case SERVER.REQUEST:
 			return {