diff --git a/lib/utils/config.ts b/lib/utils/config.ts
index b8b547f4..7c709eac 100644
--- a/lib/utils/config.ts
+++ b/lib/utils/config.ts
@@ -1,12 +1,12 @@
 import {ipcRenderer, remote} from 'electron';
 
-const plugins = remote.require('./plugins');
+const plugins = remote.require('./plugins') as typeof import('../../app/plugins');
 
 export function getConfig() {
   return plugins.getDecoratedConfig();
 }
 
-export function subscribe(fn) {
+export function subscribe(fn: (event: Electron.IpcRendererEvent, ...args: any[]) => void) {
   ipcRenderer.on('config change', fn);
   ipcRenderer.on('plugins change', fn);
   return () => {
diff --git a/lib/utils/effects.ts b/lib/utils/effects.ts
index db1cc61b..88b2b7a3 100644
--- a/lib/utils/effects.ts
+++ b/lib/utils/effects.ts
@@ -7,7 +7,7 @@
  * as the result of an action being triggered.
  */
 
-export default () => next => action => {
+export default () => (next: (arg0: any) => any) => (action: {effect: () => void}) => {
   const ret = next(action);
   if (action.effect) {
     action.effect();
diff --git a/lib/utils/notify.ts b/lib/utils/notify.ts
index 7e87c1d2..1e313ee0 100644
--- a/lib/utils/notify.ts
+++ b/lib/utils/notify.ts
@@ -1,5 +1,5 @@
 /* eslint no-new:0 */
-export default function notify(title, body, details = {}) {
+export default function notify(title: string, body: string, details: Record<string, any> = {}) {
   //eslint-disable-next-line no-console
   console.log(`[Notification] ${title}: ${body}`);
   if (details.error) {
diff --git a/lib/utils/object.ts b/lib/utils/object.ts
index 10f5d238..08f9335f 100644
--- a/lib/utils/object.ts
+++ b/lib/utils/object.ts
@@ -1,6 +1,6 @@
 const valsCache = new WeakMap();
 
-export function values(imm) {
+export function values(imm: Record<string, any>) {
   if (!valsCache.has(imm)) {
     valsCache.set(imm, Object.values(imm));
   }
@@ -8,7 +8,7 @@ export function values(imm) {
 }
 
 const keysCache = new WeakMap();
-export function keys(imm) {
+export function keys(imm: Record<string, any>) {
   if (!keysCache.has(imm)) {
     keysCache.set(imm, Object.keys(imm));
   }
diff --git a/lib/utils/paste.ts b/lib/utils/paste.ts
index a77b15ab..51120943 100644
--- a/lib/utils/paste.ts
+++ b/lib/utils/paste.ts
@@ -1,12 +1,12 @@
 import {clipboard} from 'electron';
 import plist from 'plist';
 
-const getPath = platform => {
+const getPath = (platform: string) => {
   switch (platform) {
     case 'darwin': {
       if (clipboard.has('NSFilenamesPboardType')) {
         // Parse plist file containing the path list of copied files
-        const list = plist.parse(clipboard.read('NSFilenamesPboardType'));
+        const list = plist.parse(clipboard.read('NSFilenamesPboardType')) as plist.PlistArray;
         return "'" + list.join("' '") + "'";
       } else {
         return null;
diff --git a/lib/utils/rpc.ts b/lib/utils/rpc.ts
index 3fdfe4ab..dbdfa860 100644
--- a/lib/utils/rpc.ts
+++ b/lib/utils/rpc.ts
@@ -1,7 +1,11 @@
+import {EventEmitter} from 'events';
+import {IpcRenderer, IpcRendererEvent} from 'electron';
+import electron from 'electron';
 export default class Client {
+  emitter: EventEmitter;
+  ipc: IpcRenderer;
+  id!: string;
   constructor() {
-    const electron = window.require('electron');
-    const EventEmitter = window.require('events');
     this.emitter = new EventEmitter();
     this.ipc = electron.ipcRenderer;
     this.ipcListener = this.ipcListener.bind(this);
@@ -12,7 +16,7 @@ export default class Client {
         this.emitter.emit('ready');
       }, 0);
     } else {
-      this.ipc.on('init', (ev, uid) => {
+      this.ipc.on('init', (ev: IpcRendererEvent, uid: string) => {
         // we cache so that if the object
         // gets re-instantiated we don't
         // wait for a `init` event
@@ -24,26 +28,26 @@ export default class Client {
     }
   }
 
-  ipcListener(event, {ch, data}) {
+  ipcListener(event: any, {ch, data}: {ch: string; data: any}) {
     this.emitter.emit(ch, data);
   }
 
-  on(ev, fn) {
+  on(ev: string, fn: (...args: any[]) => void) {
     this.emitter.on(ev, fn);
   }
 
-  once(ev, fn) {
+  once(ev: string, fn: (...args: any[]) => void) {
     this.emitter.once(ev, fn);
   }
 
-  emit(ev, data) {
+  emit(ev: string, data: any) {
     if (!this.id) {
       throw new Error('Not ready');
     }
     this.ipc.send(this.id, {ev, data});
   }
 
-  removeListener(ev, fn) {
+  removeListener(ev: string, fn: (...args: any[]) => void) {
     this.emitter.removeListener(ev, fn);
   }
 
@@ -53,6 +57,6 @@ export default class Client {
 
   destroy() {
     this.removeAllListeners();
-    this.ipc.removeAllListeners();
+    this.ipc.removeAllListeners(this.id);
   }
 }
diff --git a/lib/utils/term-groups.ts b/lib/utils/term-groups.ts
index 4b8c6bd6..f012f5ea 100644
--- a/lib/utils/term-groups.ts
+++ b/lib/utils/term-groups.ts
@@ -1,4 +1,7 @@
-export default function findBySession(termGroupState, sessionUid) {
+import {ITermState} from '../hyper';
+import {Immutable} from 'seamless-immutable';
+
+export default function findBySession(termGroupState: Immutable<ITermState>, sessionUid: string) {
   const {termGroups} = termGroupState;
   return Object.keys(termGroups)
     .map(uid => termGroups[uid])