diff --git a/modules/ad_spiroBidAdapter.ts b/modules/ad_spiroBidAdapter.ts
index 1604e0d1ece..0bd4258327f 100644
--- a/modules/ad_spiroBidAdapter.ts
+++ b/modules/ad_spiroBidAdapter.ts
@@ -8,6 +8,7 @@ import {
 import { ajax } from '../src/ajax.js';
 import { AUDIO, BANNER, NATIVE, VIDEO } from '../src/mediaTypes.js';
 import { isPlainObject, logWarn } from '../src/utils.js';
+import type { ORTBResponse } from '../src/prebid.public.js';
 
 /**
  * Adspiro bid parameters.
@@ -106,7 +107,7 @@ export const spec: BidderSpec<typeof BIDDER_CODE> = {
     if (!isPlainObject(serverResponse?.body)) {
       return [];
     }
-    const { bids } = converter.fromORTB({ request: request.data, response: serverResponse.body }) as ExtendedResponse;
+    const { bids } = converter.fromORTB({ request: request.data, response: serverResponse.body as ORTBResponse }) as ExtendedResponse;
     return bids;
   },
 
diff --git a/modules/asterioBidAdapter.ts b/modules/asterioBidAdapter.ts
index 09290422025..941b4848234 100644
--- a/modules/asterioBidAdapter.ts
+++ b/modules/asterioBidAdapter.ts
@@ -43,6 +43,9 @@ type AsterioServerBid = {
   mediaType?: string;
   format?: string;
   adomain?: string[];
+  vastXml?: string;
+  native?: AsterioNativeBid;
+  meta?: Record<string, any>;
 };
 
 type AsterioNativeImage = {
diff --git a/modules/multibid/index.ts b/modules/multibid/index.ts
index a7b103baa53..daa19ba0bfc 100644
--- a/modules/multibid/index.ts
+++ b/modules/multibid/index.ts
@@ -3,6 +3,7 @@
  * @module modules/multibid
  */
 
+import type { Bid } from '../../src/bidfactory.ts';
 import { config } from '../../src/config.js';
 import { getHook, setupBeforeHookFnOnce } from '../../src/hook.js';
 import { deepAccess, deepSetValue, getUniqueIdentifierStr, groupBy, logWarn } from '../../src/utils.js';
@@ -210,7 +211,7 @@ export function aliasedBiddersFirst(a, b) {
  * @param {Number} adUnitBidLimit bidder targeting limit, default set to 0
  * @param {Boolean} hasModified default set to false, this hook modifies targeting and sets to true
  */
-export function targetBidPoolHook(fn, bidsReceived, winReducer, adUnitBidLimit = 0, hasModified = false, winSorter = highestDesirabilityFirst) {
+export function targetBidPoolHook(fn, bidsReceived: Bid[], winReducer, adUnitBidLimit = 0, hasModified = false, winSorter = highestDesirabilityFirst) {
   if (!config.getConfig('multibid')) resetMultiConfig();
   if (hasMultibid) {
     const modifiedBids = [];
diff --git a/src/adRendering.ts b/src/adRendering.ts
index ea310758959..5d1857d6210 100644
--- a/src/adRendering.ts
+++ b/src/adRendering.ts
@@ -214,14 +214,14 @@ export const getRenderingData = hook('sync', function (bidResponse: Bid, options
   };
 });
 
-function prepareBidForRendering(bidResponse: Bid, options?: RenderOptions): Bid {
+function prepareBidForRendering<T extends Bid>(bidResponse: T, options?: RenderOptions): T {
   const { ad, adUrl, cpm, originalCpm, safeRenderer } = bidResponse;
   const repl = {
     AUCTION_PRICE: originalCpm || cpm,
     CLICKTHROUGH: options?.clickUrl || ''
   };
 
-  const result = {
+  const result: T = {
     ...bidResponse,
     ad: replaceMacros(ad, repl),
     adUrl: replaceMacros(adUrl, repl)
diff --git a/src/adapterManager.ts b/src/adapterManager.ts
index c3699037980..48c824051b8 100644
--- a/src/adapterManager.ts
+++ b/src/adapterManager.ts
@@ -80,7 +80,7 @@ export const PBS_ADAPTER_NAME = 'pbsBidAdapter';
 export const PARTITIONS = {
   CLIENT: 'client',
   SERVER: 'server'
-};
+} as const;
 
 export const dep = {
   isAllowed: isActivityAllowed,
@@ -440,7 +440,7 @@ export function getS2SBidderSet(s2sConfigs) {
  * @returns {Object} return.client - Array of bidder codes that should be routed to client adapters.
  * @returns {Object} return.server - Array of bidder codes that should be routed to server adapters.
  */
-export function _partitionBidders (adUnits, s2sConfigs, { getS2SBidders = getS2SBidderSet } = {}) {
+export function _partitionBidders (adUnits, s2sConfigs, { getS2SBidders = getS2SBidderSet } = {}): { [PARTITIONS.CLIENT]: string[], [PARTITIONS.SERVER]: string[] } {
   const serverBidders = getS2SBidders(s2sConfigs);
   return getBidderCodes(adUnits).reduce((memo, bidder) => {
     const partition = serverBidders.has(bidder) ? PARTITIONS.SERVER : PARTITIONS.CLIENT;
diff --git a/src/types/local/safeframe.d.ts b/src/types/local/safeframe.d.ts
new file mode 100644
index 00000000000..8c44be83f04
--- /dev/null
+++ b/src/types/local/safeframe.d.ts
@@ -0,0 +1,37 @@
+import type { SafeFrameGeometry } from '../../utils.ts';
+
+declare global {
+  interface Window {
+    $sf?: SafeFrameAPI;
+  }
+
+  interface SafeFrameAPI {
+    ext: SafeFrameExternalAPI;
+  }
+
+  interface SafeFrameExternalAPI {
+    register(
+      width: number,
+      height: number,
+      notify?: (event: string, data?: unknown) => void
+    ): void;
+
+    expand(dimensions?: {
+      t?: number;
+      b?: number;
+      l?: number;
+      r?: number;
+      push?: boolean;
+    }): void;
+
+    collapse(): void;
+
+    geom(): SafeFrameGeometry;
+
+    inViewPercentage(): number;
+
+    status(): string;
+
+    supports(feature: string): boolean;
+  }
+}
diff --git a/src/types/local/scheduler.d.ts b/src/types/local/scheduler.d.ts
new file mode 100644
index 00000000000..f75505a464b
--- /dev/null
+++ b/src/types/local/scheduler.d.ts
@@ -0,0 +1,21 @@
+export {};
+declare global {
+  type TaskPriority = "user-blocking" | "user-visible" | "background";
+
+  interface SchedulerPostTaskOptions {
+    delay?: number;
+    priority?: TaskPriority;
+    signal?: AbortSignal;
+  }
+
+  interface Scheduler {
+    postTask<T, P extends readonly unknown[] | []>(callback: (...params: P) => T, options?: SchedulerPostTaskOptions, ...arguments: P): Promise<T>;
+  }
+
+  interface Window {
+    /**
+     * https://github.com/microsoft/TypeScript-DOM-lib-generator/pull/1249
+     */
+    scheduler?: Scheduler;
+  }
+}
diff --git a/src/utils.js b/src/utils.ts
similarity index 75%
rename from src/utils.js
rename to src/utils.ts
index 29e4a07682c..639ad45204e 100644
--- a/src/utils.js
+++ b/src/utils.ts
@@ -1,12 +1,12 @@
 import { config } from './config.js';
 
 import { PbPromise } from './utils/promise.js';
-import deepAccess from 'dlv/index.js';
+import dlv from 'dlv/index.js';
 import { isArray, isFn, isPlainObject, isStr } from './utils/objects.js';
 import * as logging from './utils/logging.js';
 import * as debug from './utils/debug.js';
 
-export { deepAccess };
+export const deepAccess: (obj: any, path: string | ReadonlyArray<string | number>, def?: any) => any = dlv;
 export { dset as deepSetValue } from 'dset';
 export * from './utils/objects.js';
 export { getWinDimensions, resetWinDimensions, getScreenOrientation } from './utils/winDimensions.js';
@@ -44,21 +44,21 @@ const prebidInternal = {};
 /**
  * Returns object that is used as internal prebid namespace
  */
-export function getPrebidInternal() {
+export function getPrebidInternal(): Record<string, unknown> {
   return prebidInternal;
 }
 
 /* utility method to get incremental integer starting from 1 */
-var getIncrementalInteger = (function () {
+var getIncrementalInteger = (function (): () => number {
   var count = 0;
-  return function () {
+  return function (): number {
     count++;
     return count;
   };
 })();
 
 // generate a random string (to be used as a dynamic JSONP callback)
-export function getUniqueIdentifierStr() {
+export function getUniqueIdentifierStr(): string {
   return getIncrementalInteger() + Math.random().toString(16).substring(2);
 }
 
@@ -68,17 +68,17 @@ export function getUniqueIdentifierStr() {
  * and y is replaced with a random hexadecimal digit from 8 to b.
  * https://gist.github.com/jed/982883 via node-uuid
  */
-export function generateUUID(placeholder) {
+export function generateUUID(placeholder?: number | string): string {
   return placeholder
-    ? (placeholder ^ _getRandomData() >> placeholder / 4).toString(16)
-    : ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, generateUUID);
+    ? (Number(placeholder) ^ _getRandomData() >> Number(placeholder) / 4).toString(16)
+    : ('' + [1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, generateUUID);
 }
 
 /**
  * Returns random data using the Crypto API if available and Math.random if not
  * Method is from https://gist.github.com/jed/982883 like generateUUID, direct link https://gist.github.com/jed/982883#gistcomment-45104
  */
-function _getRandomData() {
+function _getRandomData(): number {
   if (window && window.crypto && window.crypto.getRandomValues) {
     return window.crypto.getRandomValues(new Uint8Array(1))[0] % 16;
   } else {
@@ -86,14 +86,14 @@ function _getRandomData() {
   }
 }
 
-export function getBidIdParameter(key, paramsObj) {
+export function getBidIdParameter(key: string, paramsObj: Record<string, any>): string {
   return paramsObj?.[key] || '';
 }
 
 // parse a query string object passed in bid params
 // bid params should be an object such as {key: "value", key1 : "value1"}
 // aliases to formatQS
-export function parseQueryStringParameters(queryObj) {
+export function parseQueryStringParameters(queryObj: Record<string, any>): string {
   let result = '';
   for (var k in queryObj) {
     if (queryObj.hasOwnProperty(k)) { result += k + '=' + encodeURIComponent(queryObj[k]) + '&'; }
@@ -103,7 +103,7 @@ export function parseQueryStringParameters(queryObj) {
 }
 
 // transform an AdServer targeting bids into a query string to send to the adserver
-export function transformAdServerTargetingObj(targeting) {
+export function transformAdServerTargetingObj(targeting: Record<string, any>): string {
   // we expect to receive targeting for a single slot at a time
   if (targeting && Object.getOwnPropertyNames(targeting).length > 0) {
     return Object.keys(targeting)
@@ -116,7 +116,7 @@ export function transformAdServerTargetingObj(targeting) {
 /**
  * Parse a GPT-Style general size Array like `[[300, 250]]` or `"300x250,970x90"` into an array of width, height tuples `[[300, 250]]` or '[[300,250], [970,90]]'
  */
-export function sizesToSizeTuples(sizes) {
+export function sizesToSizeTuples(sizes: string | number[] | number[][] | unknown): [number, number][] {
   if (typeof sizes === 'string') {
     // multiple sizes will be comma-separated
     return sizes
@@ -138,56 +138,56 @@ export function sizesToSizeTuples(sizes) {
  * @param  {(Array.<number[]>|Array.<number>)} sizeObj Input array or double array [300,250] or [[300,250], [728,90]]
  * @return {Array.<string>}  Array of strings like `["300x250"]` or `["300x250", "728x90"]`
  */
-export function parseSizesInput(sizeObj) {
+export function parseSizesInput(sizeObj: string | number[] | number[][]): string[] {
   return sizesToSizeTuples(sizeObj).map(sizeTupleToSizeString);
 }
 
-export function sizeTupleToSizeString(size) {
+export function sizeTupleToSizeString(size: [number, number]): string {
   return size[0] + 'x' + size[1];
 }
 
 // Parse a GPT style single size array, (i.e [300, 250])
 // into an AppNexus style string, (i.e. 300x250)
-export function parseGPTSingleSizeArray(singleSize) {
+export function parseGPTSingleSizeArray(singleSize: number[]): string | undefined {
   if (isValidGPTSingleSize(singleSize)) {
     return sizeTupleToSizeString(singleSize);
   }
 }
 
-export function sizeTupleToRtbSize(size) {
+export function sizeTupleToRtbSize(size: [number, number]): { w: number; h: number } {
   return { w: size[0], h: size[1] };
 }
 
 // Parse a GPT style single size array, (i.e [300, 250])
 // into OpenRTB-compatible (imp.banner.w/h, imp.banner.format.w/h, imp.video.w/h) object(i.e. {w:300, h:250})
-export function parseGPTSingleSizeArrayToRtbSize(singleSize) {
+export function parseGPTSingleSizeArrayToRtbSize(singleSize: number[]): { w: number; h: number } | undefined {
   if (isValidGPTSingleSize(singleSize)) {
     return sizeTupleToRtbSize(singleSize);
   }
 }
 
-function isValidGPTSingleSize(singleSize) {
+function isValidGPTSingleSize(singleSize: unknown): singleSize is [number, number] {
   // if we aren't exactly 2 items in this array, it is invalid
   return isArray(singleSize) && singleSize.length === 2 && (!isNaN(singleSize[0]) && !isNaN(singleSize[1]));
 }
 
-export function getWindowTop() {
+export function getWindowTop(): Window {
   return window.top;
 }
 
-export function getWindowSelf() {
+export function getWindowSelf(): Window {
   return window.self;
 }
 
-export function getWindowLocation() {
+export function getWindowLocation(): Location {
   return window.location;
 }
 
-export function getDocument() {
+export function getDocument(): Document {
   return document;
 }
 
-export function canAccessWindowTop() {
+export function canAccessWindowTop(): boolean {
   try {
     if (internal.getWindowTop().location.href) {
       return true;
@@ -202,7 +202,7 @@ export function canAccessWindowTop() {
  * @param {Window} [win]
  * @returns {Window}
  */
-export function getFallbackWindow(win) {
+export function getFallbackWindow(win?: Window): Window {
   if (win) {
     return win;
   }
@@ -220,7 +220,7 @@ export const createIframe = (() => {
     frameBorder: '0',
     allowtransparency: 'true'
   };
-  return (doc, attrs, style = {}) => {
+  return (doc: Document, attrs: Record<string, any>, style: Record<string, string> = {}) => {
     const f = doc.createElement('iframe');
     Object.assign(f, Object.assign({}, DEFAULTS, attrs));
     Object.assign(f.style, style);
@@ -228,7 +228,7 @@ export const createIframe = (() => {
   };
 })();
 
-export function createInvisibleIframe(doc = document, attrs = {}, style = {}) {
+export function createInvisibleIframe(doc: Document = document, attrs = {}, style = {}): HTMLIFrameElement {
   return createIframe(doc, {
     id: getUniqueIdentifierStr(),
     width: 0,
@@ -248,7 +248,7 @@ export function createInvisibleIframe(doc = document, attrs = {}, style = {}) {
  *   Check if a given parameter name exists in query string
  *   and if it does return the value
  */
-export function getParameterByName(name) {
+export function getParameterByName(name: string): string {
   return parseQS(getWindowLocation().search)[name] || '';
 }
 
@@ -258,12 +258,12 @@ export function getParameterByName(name) {
  * @param {*} object object to test
  * @return {Boolean} if object is empty
  */
-export function isEmpty(object) {
+export function isEmpty(object: unknown): boolean {
   if (!object) return true;
   if (isArray(object) || isStr(object)) {
-    return !(object.length > 0);
+    return !((object as { length: number }).length > 0);
   }
-  return Object.keys(object).length <= 0;
+  return Object.keys(object as Record<string, unknown>).length <= 0;
 }
 
 /**
@@ -271,7 +271,7 @@ export function isEmpty(object) {
  * @param str string to test
  * @returns {boolean} if string is empty
  */
-export function isEmptyStr(str) {
+export function isEmptyStr(str: unknown): boolean {
   return isStr(str) && (!str || str.length === 0);
 }
 
@@ -282,13 +282,13 @@ export function isEmptyStr(str) {
  * @param {Function} fn - The function to execute for each element. It receives three arguments: value, key, and the original object.
  * @returns {void}
  */
-export function _each(object, fn) {
+export function _each<T>(object: T[] | Record<string, T>, fn: (value: T, key: any) => void): void {
   if (isFn(object?.forEach)) return object.forEach(fn, this);
   Object.entries(object || {}).forEach(([k, v]) => fn.call(this, v, k));
 }
 
-export function contains(a, obj) {
-  return isFn(a?.includes) && a.includes(obj);
+export function contains(a: unknown, obj: unknown): boolean {
+  return isFn((a as { includes?: unknown })?.includes) && (a as { includes: (o: unknown) => boolean }).includes(obj);
 }
 
 /**
@@ -298,7 +298,7 @@ export function contains(a, obj) {
  * @param {Function} callback - The function to execute for each element. It receives three arguments: value, key, and the original object.
  * @return {Array}
  */
-export function _map(object, callback) {
+export function _map<T, R>(object: T[] | Record<string, T>, callback: (value: T, key: any, obj?: T[] | Record<string, T>) => R): R[] {
   if (isFn(object?.map)) return object.map(callback);
   return Object.entries(object || {}).map(([k, v]) => callback(v, k, object));
 }
@@ -311,7 +311,7 @@ export function _map(object, callback) {
 * @param {Boolean} [asLastChildChild]
 * @return {HTML Element}
 */
-export function insertElement(elm, doc, target, asLastChildChild) {
+export function insertElement(elm: Node, doc?: Document, target?: string, asLastChildChild?: boolean): Node | undefined {
   doc = doc || document;
   let parentEl;
   if (target) {
@@ -337,9 +337,9 @@ export function insertElement(elm, doc, target, asLastChildChild) {
  * @param {Number} [timeout]
  * @returns {Promise}
  */
-export function waitForElementToLoad(element, timeout) {
-  let timer = null;
-  return new PbPromise((resolve) => {
+export function waitForElementToLoad(element: HTMLElement, timeout?: number): Promise<void> {
+  let timer: number | null = null;
+  return new PbPromise<void>((resolve) => {
     const onLoad = function() {
       element.removeEventListener('load', onLoad);
       element.removeEventListener('error', onLoad);
@@ -364,7 +364,7 @@ export function waitForElementToLoad(element, timeout) {
  *   `'omit'` for a cookieless request — the image fallback (which cannot omit cookies) is then skipped.
  */
 
-export function politeTriggerPixel(url, credentials = 'include') {
+export function politeTriggerPixel(url: string, credentials: RequestCredentials = 'include'): void {
   const triggerSync = () => {
     if (window.fetch && window.Request) {
       try {
@@ -384,7 +384,7 @@ export function politeTriggerPixel(url, credentials = 'include') {
   runBackgroundTask(triggerSync);
 }
 
-export function triggerPixel(url, done, timeout) {
+export function triggerPixel(url: string, done?: () => void, timeout?: number): void {
   const img = new Image();
   if (done && internal.isFn(done)) {
     waitForElementToLoad(img, timeout).then(done);
@@ -396,7 +396,7 @@ export function triggerPixel(url, done, timeout) {
  * Run a task at low priority when supported by the browser, or immediately as fallback.
  * @param {function} task
  */
-export function runBackgroundTask(task) {
+export function runBackgroundTask(task: () => void): void {
   const scheduler = window.scheduler;
   if (scheduler?.postTask) {
     scheduler.postTask(task, { priority: 'background' }).catch(() => task());
@@ -414,7 +414,7 @@ export function runBackgroundTask(task) {
  * (though could be for other purposes)
  * @param {string} htmlCode snippet of HTML code used for tracking purposes
  */
-export function insertHtmlIntoIframe(htmlCode) {
+export function insertHtmlIntoIframe(htmlCode: string): void {
   if (!htmlCode) {
     return;
   }
@@ -434,7 +434,7 @@ export function insertHtmlIntoIframe(htmlCode) {
  * @param encode
  * @return {string}     HTML snippet that contains the img src = set to `url`
  */
-export function createTrackPixelHtml(url, encode = encodeURI) {
+export function createTrackPixelHtml(url: string, encode: (url: string) => string = encodeURI): string {
   if (!url) {
     return '';
   }
@@ -470,7 +470,7 @@ const MACRO = /\$\{([^}#$&+,/:;=?@]+)\}/g;
  * @param url
  * @return {string}
  */
-export function encodeMacroURI(url) {
+export function encodeMacroURI(url): string {
   let encoded = '';
   let from = 0;
   for (const match of url.matchAll(MACRO)) {
@@ -481,15 +481,15 @@ export function encodeMacroURI(url) {
   return encoded + encodeURI(url.slice(from));
 }
 
-export function uniques(value, index, arry) {
+export function uniques<T>(value: T, index: number, arry: T[]) {
   return arry.indexOf(value) === index;
 }
 
-export function flatten(a, b) {
+export function flatten<T>(a: T[], b: T | T[]) {
   return a.concat(b);
 }
 
-export function getBidRequest(id, bidderRequests) {
+export function getBidRequest(id: string, bidderRequests: Array<{ bids: any[] }>): Record<string, any> | undefined {
   if (!id) {
     return;
   }
@@ -497,29 +497,25 @@ export function getBidRequest(id, bidderRequests) {
     .find(bid => ['bidId', 'adId', 'bid_id'].some(prop => bid[prop] === id));
 }
 
-export function getValue(obj, key) {
+export function getValue(obj: Record<string, unknown>, key: string): unknown {
   return obj[key];
 }
 
-export function getBidderCodes(adUnits) {
+export function getBidderCodes(adUnits: Array<{ bids?: Array<{ bidder?: string }> }>): string[] {
   // this could memoize adUnits
   return adUnits.map(unit => unit.bids.map(bid => bid.bidder)
     .reduce(flatten, [])).reduce(flatten, []).filter((bidder) => typeof bidder !== 'undefined').filter(uniques);
 }
 
-export function isGptPubadsDefined() {
-  if (window.googletag && isFn(window.googletag.pubads) && isFn(window.googletag.pubads().getSlots)) {
-    return true;
-  }
+export function isGptPubadsDefined(): boolean {
+  return !!(window.googletag && isFn(window.googletag.pubads) && isFn(window.googletag.pubads().getSlots));
 }
 
-export function isApnGetTagDefined() {
-  if (window.apntag && isFn(window.apntag.getTag)) {
-    return true;
-  }
+export function isApnGetTagDefined(): boolean {
+  return !!(window.apntag && isFn(window.apntag.getTag));
 }
 
-export const sortByHighestCpm = (a, b) => {
+export const sortByHighestCpm = (a: { cpm: number }, b: { cpm: number }): number => {
   return b.cpm - a.cpm;
 };
 
@@ -529,7 +525,7 @@ export const sortByHighestCpm = (a, b) => {
  * https://bost.ocks.org/mike/shuffle/
  * istanbul ignore next
  */
-export function shuffle(array) {
+export function shuffle<T>(array: T[]): T[] {
   let counter = array.length;
 
   // while there are elements in the array
@@ -549,7 +545,7 @@ export function shuffle(array) {
   return array;
 }
 
-export function inIframe() {
+export function inIframe(): boolean {
   try {
     return internal.getWindowSelf() !== internal.getWindowTop();
   } catch (e) {
@@ -560,7 +556,7 @@ export function inIframe() {
 /**
  * https://iabtechlab.com/wp-content/uploads/2016/03/SafeFrames_v1.1_final.pdf
  */
-export function isSafeFrameWindow() {
+export function isSafeFrameWindow(): boolean {
   if (!inIframe()) {
     return false;
   }
@@ -569,50 +565,60 @@ export function isSafeFrameWindow() {
   return !!(ws.$sf && ws.$sf.ext);
 }
 
+/**
+ * Geometry of a SafeFrame container, as returned by `$sf.ext.geom()`.
+ */
+export interface SafeFrameGeometry {
+  self?: { x: number; y: number; w: number; h: number };
+  exp?: { t: number; b: number; l: number; r: number };
+  win?: { w: number; h: number };
+  view?: { x: number; y: number; w: number; h: number };
+}
+
 /**
  * Returns the result of calling the function $sf.ext.geom() if it exists
  * @see https://iabtechlab.com/wp-content/uploads/2016/03/SafeFrames_v1.1_final.pdf — 5.4 Function $sf.ext.geom
  * @returns {Object | undefined} geometric information about the container
  */
-export function getSafeframeGeometry() {
+export function getSafeframeGeometry(): SafeFrameGeometry | undefined {
   try {
     const ws = getWindowSelf();
-    return (typeof ws.$sf.ext.geom === 'function') ? ws.$sf.ext.geom() : undefined;
+    return isFn(ws.$sf.ext.geom) ? ws.$sf.ext.geom() : undefined;
   } catch (e) {
     logError('Error getting SafeFrame geometry', e);
     return undefined;
   }
 }
 
-export function isSafariBrowser() {
+export function isSafariBrowser(): boolean {
   return /^((?!chrome|chromium|android|crios|fxios).)*safari/i.test(navigator.userAgent);
 }
 
-export function isFirefoxBrowser() {
+export function isFirefoxBrowser(): boolean {
   return /firefox|fxios/i.test(navigator.userAgent);
 }
 
-export function isChromeIOSBrowser() {
+export function isChromeIOSBrowser(): boolean {
   return /crios|crmo/i.test(navigator.userAgent);
 }
 
-export function replaceMacros(str, subs) {
+export function replaceMacros(str: string | undefined, subs: Record<string, any>): string | undefined {
   if (!str) return;
   return Object.entries(subs).reduce((str, [key, val]) => {
     return str.replace(new RegExp('\\$\\{' + key + '\\}', 'g'), val || '');
   }, str);
 }
 
-export function replaceAuctionPrice(str, cpm) {
+export function replaceAuctionPrice(str: string | undefined, cpm: number | string): string | undefined {
   return replaceMacros(str, { AUCTION_PRICE: cpm });
 }
 
-export function replaceClickThrough(str, clicktag) {
+export function replaceClickThrough(str: string | undefined, clicktag: string): string | undefined {
   if (!str || !clicktag || typeof clicktag !== 'string') return;
   return str.replace(/\${CLICKTHROUGH}/g, clicktag);
 }
 
-export function timestamp() {
+export function timestamp(): number {
   return new Date().getTime();
 }
 
@@ -620,7 +626,7 @@ export function timestamp() {
  * The returned value represents the time elapsed since the time origin. @see https://developer.mozilla.org/en-US/docs/Web/API/Performance/now
  * @returns {number}
  */
-export function getPerformanceNow() {
+export function getPerformanceNow(): number {
   return (window.performance && window.performance.now && window.performance.now()) || 0;
 }
 
@@ -632,7 +638,7 @@ export function getPerformanceNow() {
  * @param {Window} w The window object used to perform the api call. default to window.self
  * @returns {number}
  */
-export function getDomLoadingDuration(w) {
+export function getDomLoadingDuration(w?: Window): number {
   let domLoadingDuration = -1;
 
   w = w || getWindowSelf();
@@ -655,14 +661,14 @@ export function getDomLoadingDuration(w) {
  * When the deviceAccess flag config option is false, no cookies should be read or set
  * @returns {boolean}
  */
-export function hasDeviceAccess() {
+export function hasDeviceAccess(): boolean {
   return config.getConfig('deviceAccess') !== false;
 }
 
 /**
  * @returns {(boolean|undefined)}
  */
-export function checkCookieSupport() {
+export function checkCookieSupport(): boolean | undefined {
   // eslint-disable-next-line no-restricted-properties
   if (window.navigator.cookieEnabled || !!document.cookie.length) {
     return true;
@@ -681,15 +687,15 @@ export function checkCookieSupport() {
  * @param {number} numRequiredCalls The number of times which the returned function needs to be called before
  *   func is.
  */
-export function delayExecution(func, numRequiredCalls) {
+export function delayExecution<A extends unknown[]>(func: (...args: A) => void, numRequiredCalls: number): (...args: A) => void {
   if (numRequiredCalls < 1) {
     throw new Error(`numRequiredCalls must be a positive number. Got ${numRequiredCalls}`);
   }
   let numCalls = 0;
-  return function () {
+  return function (this: unknown, ...args: A): void {
     numCalls++;
     if (numCalls === numRequiredCalls) {
-      func.apply(this, arguments);
+      func.apply(this, args);
     }
   };
 }
@@ -700,9 +706,10 @@ export function delayExecution(func, numRequiredCalls) {
  * @param {string} key
  * @returns {Object} {${key_value}: ${groupByArray}, key_value: {groupByArray}}
  */
-export function groupBy(xs, key) {
-  return xs.reduce(function(rv, x) {
-    (rv[x[key]] = rv[x[key]] || []).push(x);
+export function groupBy<T>(xs: T[], key: string): Record<string, T[]> {
+  return xs.reduce(function(rv: Record<string, T[]>, x) {
+    const k = String((x as Record<string, unknown>)[key]);
+    (rv[k] = rv[k] || []).push(x);
     return rv;
   }, {});
 }
@@ -712,7 +719,7 @@ export function groupBy(xs, key) {
  * @param mediaTypes mediaTypes parameter to validate
  * @return If object is valid
  */
-export function isValidMediaTypes(mediaTypes) {
+export function isValidMediaTypes(mediaTypes: Record<string, any>): boolean {
   const SUPPORTED_MEDIA_TYPES = ['banner', 'native', 'video', 'audio'];
   const SUPPORTED_STREAM_TYPES = ['instream', 'outstream'];
 
@@ -736,7 +743,7 @@ export function isValidMediaTypes(mediaTypes) {
  * @param {string} bidder code
  * @return {Array} user configured param for the given bidder adunit configuration
  */
-export function getUserConfiguredParams(adUnits, adUnitCode, bidder) {
+export function getUserConfiguredParams(adUnits: Array<{ code: string; bids: Array<{ bidder: string; params?: Record<string, unknown> }> }>, adUnitCode: string, bidder: string): Record<string, unknown>[] {
   return adUnits
     .filter(adUnit => adUnit.code === adUnitCode)
     .flatMap((adUnit) => adUnit.bids)
@@ -744,26 +751,28 @@ export function getUserConfiguredParams(adUnits, adUnitCode, bidder) {
     .map((bidderData) => bidderData.params || {});
 }
 
-export const compareCodeAndSlot = (slot, adUnitCode) => slot.getAdUnitPath() === adUnitCode || slot.getSlotElementId() === adUnitCode;
+export const compareCodeAndSlot = (slot: googletag.Slot, adUnitCode: string) => slot.getAdUnitPath() === adUnitCode || slot.getSlotElementId() === adUnitCode;
 
 /**
  * Returns filter function to match adUnitCode in slot
  * @param slot GoogleTag slot
  * @return filter function
  */
-export function isAdUnitCodeMatchingSlot(slot) {
+export function isAdUnitCodeMatchingSlot(slot: googletag.Slot): (adUnitCode: string) => boolean {
   const customGptSlotMatching = config.getConfig('customGptSlotMatching');
   const match = isFn(customGptSlotMatching) && customGptSlotMatching(slot);
-  return isFn(match) ? match : (adUnitCode) => compareCodeAndSlot(slot, adUnitCode);
+  return isFn(match) ? match : (adUnitCode: string) => compareCodeAndSlot(slot, adUnitCode);
 }
 
 /**
  * Constructs warning message for when unsupported bidders are dropped from an adunit
  * @param {Object} adUnit ad unit from which the bidder is being dropped
+ * @param {string} adUnit.code the ad unit code
+ * @param {Object} [adUnit.mediaTypes] the ad unit media types
  * @param {string} bidder bidder code that is not compatible with the adUnit
  * @return {string} warning message to display when condition is met
  */
-export function unsupportedBidderMessage(adUnit, bidder) {
+export function unsupportedBidderMessage(adUnit: { code: string; mediaTypes?: Record<string, any> }, bidder: string): string {
   const mediaType = Object.keys(adUnit.mediaTypes || { 'banner': 'banner' }).join(', ');
 
   return `
@@ -777,7 +786,7 @@ export function unsupportedBidderMessage(adUnit, bidder) {
  * Returns a new object with undefined properties removed from given object
  * @param obj the object to clean
  */
-export function cleanObj(obj) {
+export function cleanObj(obj: Record<string, any>): Record<string, any> {
   return Object.fromEntries(Object.entries(obj).filter(([_, v]) => typeof v !== 'undefined'));
 }
 
@@ -786,7 +795,7 @@ export function cleanObj(obj) {
  * @param obj the original object
  * @param properties An array of desired properties
  */
-export function pick(obj, properties) {
+export function pick(obj: Record<string, any>, properties: ReadonlyArray<string | ((...args: any[]) => any)>): Record<string, any> {
   if (typeof obj !== 'object') {
     return {};
   }
@@ -805,7 +814,7 @@ export function pick(obj, properties) {
 
     let value = obj[prop];
     if (typeof properties[i + 1] === 'function') {
-      value = properties[i + 1](value, newObj);
+      value = (properties[i + 1] as (...args: any[]) => any)(value, newObj);
     }
     if (typeof value !== 'undefined') {
       newObj[newProp] = value;
@@ -815,7 +824,7 @@ export function pick(obj, properties) {
   }, {});
 }
 
-export function parseQS(query) {
+export function parseQS(query: string): Record<string, any> {
   return !query ? {} : query
     .replace(/^\?/, '')
     .split('&')
@@ -832,7 +841,7 @@ export function parseQS(query) {
     }, {});
 }
 
-export function formatQS(query) {
+export function formatQS(query: Record<string, any>): string {
   return Object
     .keys(query)
     .map(k => Array.isArray(query[k])
@@ -841,7 +850,16 @@ export function formatQS(query) {
     .join('&');
 }
 
-export function parseUrl(url, options) {
+export function parseUrl(url: string, options?: Record<string, any>): {
+  href: string;
+  protocol: string;
+  hostname: string;
+  port: number;
+  pathname: string;
+  search: any;
+  hash: string;
+  host: string;
+} {
   const parsed = document.createElement('a');
   if (options && 'noDecodeWholeURL' in options && options.noDecodeWholeURL) {
     parsed.href = url;
@@ -856,18 +874,18 @@ export function parseUrl(url, options) {
     hostname: parsed.hostname,
     port: +parsed.port,
     pathname: parsed.pathname.replace(/^(?!\/)/, '/'),
-    search: (qsAsString) ? parsed.search : internal.parseQS(parsed.search || ''),
+    search: (qsAsString ? parsed.search : internal.parseQS(parsed.search || '')) as any,
     hash: (parsed.hash || '').replace(/^#/, ''),
     host: parsed.host || window.location.host
   };
 }
 
-export function buildUrl(obj) {
+export function buildUrl(obj: { protocol?: string; host?: string; hostname?: string; port?: number; pathname?: string; search?: string | Record<string, any>; hash?: string }): string {
   return (obj.protocol || 'http') + '://' +
     (obj.host ||
       obj.hostname + (obj.port ? `:${obj.port}` : '')) +
     (obj.pathname || '') +
-    (obj.search ? `?${internal.formatQS(obj.search || '')}` : '') +
+    (obj.search ? `?${internal.formatQS(obj.search as Record<string, any>)}` : '') +
     (obj.hash ? `#${obj.hash}` : '');
 }
 
@@ -879,7 +897,7 @@ export function buildUrl(obj) {
  * @param {boolean} [options.checkTypes=false] - If set, two objects with identical properties but different constructors will *not* be considered equivalent.
  * @returns {boolean} - Returns `true` if the objects are equivalent, `false` otherwise.
  */
-export function deepEqual(obj1, obj2, { checkTypes = false } = {}) {
+export function deepEqual(obj1: any, obj2: any, { checkTypes = false } = {}): boolean {
   // Quick reference check
   if (obj1 === obj2) return true;
 
@@ -930,7 +948,7 @@ export function deepEqual(obj1, obj2, { checkTypes = false } = {}) {
   return true;
 }
 
-export function mergeDeep(target, ...sources) {
+export function mergeDeep(target: Record<string, any>, ...sources: any[]): any {
   for (let i = 0; i < sources.length; i++) {
     const source = sources[i];
     if (!isPlainObject(source)) {
@@ -941,7 +959,7 @@ export function mergeDeep(target, ...sources) {
   return target;
 }
 
-function mergeDeepHelper(target, source) {
+function mergeDeepHelper(target: any, source: any): void {
   // quick check
   if (!isPlainObject(target) || !isPlainObject(source)) {
     return;
@@ -965,9 +983,10 @@ function mergeDeepHelper(target, source) {
         target[key] = [...val];
       } else {
         // deduplicate
+        const targetArr = target[key] as any[];
         val.forEach(obj => {
-          if (!target[key].some(item => deepEqual(item, obj))) {
-            target[key].push(obj);
+          if (!targetArr.some(item => deepEqual(item, obj))) {
+            targetArr.push(obj);
           }
         });
       }
@@ -985,10 +1004,8 @@ function mergeDeepHelper(target, source) {
  * @param seed (optional)
  * @returns {string}
  */
-export function cyrb53Hash(str, seed = 0) {
-  // IE doesn't support imul
-  // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/imul#Polyfill
-  const imul = function(opA, opB) {
+export function cyrb53Hash(str: string, seed: number = 0): string {
+  const imul = function(opA: number, opB: number) {
     if (isFn(Math.imul)) {
       return Math.imul(opA, opB);
     } else {
@@ -1008,7 +1025,7 @@ export function cyrb53Hash(str, seed = 0) {
 
   let h1 = 0xdeadbeef ^ seed;
   let h2 = 0x41c6ce57 ^ seed;
-  for (let i = 0, ch; i < str.length; i++) {
+  for (let i = 0, ch: number; i < str.length; i++) {
     ch = str.charCodeAt(i);
     h1 = imul(h1 ^ ch, 2654435761);
     h2 = imul(h2 ^ ch, 1597334677);
@@ -1023,13 +1040,13 @@ export function cyrb53Hash(str, seed = 0) {
  * @param data
  * @returns {any}
  */
-export function safeJSONParse(data) {
+export function safeJSONParse<T>(data: string): T | undefined {
   try {
     return JSON.parse(data);
   } catch (e) {}
 }
 
-export function safeJSONEncode(data) {
+export function safeJSONEncode(data: unknown): string {
   try {
     return JSON.stringify(data);
   } catch (e) {
@@ -1045,18 +1062,18 @@ export function safeJSONEncode(data) {
  *        By default, the first argument is used as key.
  * @return {*}
  */
-export function memoize(fn, key = function (arg) { return arg; }) {
+export function memoize<T extends (...args: any[]) => any>(fn: T, key: (...args: any[]) => any = (arg) => arg): ((...args: Parameters<T>) => ReturnType<T>) & { clear: () => void; invalidate: (...args: any[]) => void } {
   const cache = new Map();
-  const memoized = function () {
-    const cacheKey = key.apply(this, arguments);
+  const memoized = function (this: unknown, ...args: Parameters<T>): ReturnType<T> {
+    const cacheKey = key.apply(this, args);
     if (!cache.has(cacheKey)) {
-      cache.set(cacheKey, fn.apply(this, arguments));
+      cache.set(cacheKey, fn.apply(this, args));
     }
     return cache.get(cacheKey);
-  };
+  } as ((...args: Parameters<T>) => ReturnType<T>) & { clear: () => void; invalidate: (...args: any[]) => void };
   memoized.clear = cache.clear.bind(cache);
-  memoized.invalidate = function () {
-    cache.delete(key.apply(this, arguments));
+  memoized.invalidate = function (this: unknown, ...args: any[]) {
+    cache.delete(key.apply(this, args));
   };
   return memoized;
 }
@@ -1067,7 +1084,7 @@ export function memoize(fn, key = function (arg) { return arg; }) {
  * @param {string} timeUnit defaults to days (or 'd'), use 'm' for minutes. Any parameter that isn't 'd' or 'm' will return Date.now().
  * @returns {number}
  */
-export function getUnixTimestampFromNow(timeValue = 0, timeUnit = 'd') {
+export function getUnixTimestampFromNow(timeValue: number = 0, timeUnit: 'm' | 'd' = 'd'): number {
   const acceptableUnits = ['m', 'd'];
   if (acceptableUnits.indexOf(timeUnit) < 0) {
     return Date.now();
@@ -1084,7 +1101,7 @@ export function getUnixTimestampFromNow(timeValue = 0, timeUnit = 'd') {
  * @param {Object} obj the object
  * @returns {Array}
  */
-export function convertObjectToArray(obj) {
+export function convertObjectToArray(obj: Record<string, any>): Array<Record<string, any>> {
   return Object.keys(obj).map(key => {
     return { [key]: obj[key] };
   });
@@ -1095,7 +1112,7 @@ export function convertObjectToArray(obj) {
  * @param {HTMLScriptElement} script
  * @param {object} attributes
  */
-export function setScriptAttributes(script, attributes) {
+export function setScriptAttributes(script: HTMLScriptElement, attributes: Record<string, string>): void {
   Object.entries(attributes).forEach(([k, v]) => script.setAttribute(k, v));
 }
 
@@ -1109,7 +1126,7 @@ export function setScriptAttributes(script, attributes) {
  *   if the element is not found, return the index of the first element that's greater;
  *   if no greater element exists, return `arr.length`)
  */
-export function binarySearch(arr, el, key = (el) => el) {
+export function binarySearch<T>(arr: T[], el: T, key: (el: T) => unknown = (el) => el): number {
   let left = 0;
   let right = arr.length && arr.length - 1;
   const target = key(el);
@@ -1135,7 +1152,7 @@ export function binarySearch(arr, el, key = (el) => el) {
  * @param {Set} checkedObjects - A set of properties that have already been checked.
  * @returns {boolean} - Returns true if the object has non-serializable properties, false otherwise.
  */
-export function hasNonSerializableProperty(obj, checkedObjects = new Set()) {
+export function hasNonSerializableProperty(obj: Record<string, any>, checkedObjects: Set<unknown> = new Set()): boolean {
   for (const key in obj) {
     const value = obj[key];
     const type = typeof value;
@@ -1173,8 +1190,8 @@ export function hasNonSerializableProperty(obj, checkedObjects = new Set()) {
  * @param {String} key - Key of nested property.
  * @returns {any|undefined} - Value of nested property.
  */
-export function setOnAny(collection, key) {
-  for (let i = 0, result; i < collection.length; i++) {
+export function setOnAny(collection: unknown[], key: string): unknown {
+  for (let i = 0, result: unknown; i < collection.length; i++) {
     result = deepAccess(collection[i], key);
     if (result) {
       return result;
@@ -1183,7 +1200,7 @@ export function setOnAny(collection, key) {
   return undefined;
 }
 
-export function extractDomainFromHost(pageHost) {
+export function extractDomainFromHost(pageHost: string): string | null {
   let domain = null;
   try {
     const domains = /[-\w]+\.([-\w]+|[-\w]{3,}|[-\w]{1,3}\.[-\w]{2})$/i.exec(pageHost);
@@ -1201,11 +1218,11 @@ export function extractDomainFromHost(pageHost) {
   return domain;
 }
 
-export function triggerNurlWithCpm(bid, cpm) {
+export function triggerNurlWithCpm(bid: { nurl?: string }, cpm: number | string): void {
   if (isStr(bid.nurl) && bid.nurl !== '') {
     bid.nurl = bid.nurl.replace(
       /\${AUCTION_PRICE}/,
-      cpm
+      String(cpm)
     );
     politeTriggerPixel(bid.nurl);
   }
diff --git a/src/utils/cachedApiWrapper.js b/src/utils/cachedApiWrapper.js
deleted file mode 100644
index a36026ed98e..00000000000
--- a/src/utils/cachedApiWrapper.js
+++ /dev/null
@@ -1,26 +0,0 @@
-export function CachedApiWrapper(getTarget, props) {
-  const wrapper = {};
-  let data = {};
-  const children = [];
-  Object.entries(props).forEach(([key, value]) => {
-    if (value != null && typeof value === 'object') {
-      const child = new CachedApiWrapper(() => getTarget()?.[key], value);
-      wrapper[key] = child.obj;
-      children.push(child.reset);
-    } else if (value === true) {
-      Object.defineProperty(wrapper, key, {
-        get() {
-          if (!data.hasOwnProperty(key)) {
-            data[key] = getTarget()?.[key];
-          }
-          return data[key];
-        }
-      });
-    }
-  });
-  this.obj = wrapper;
-  this.reset = function () {
-    children.forEach(reset => reset());
-    data = {};
-  };
-}
diff --git a/src/utils/cachedApiWrapper.ts b/src/utils/cachedApiWrapper.ts
new file mode 100644
index 00000000000..e5e329f3275
--- /dev/null
+++ b/src/utils/cachedApiWrapper.ts
@@ -0,0 +1,48 @@
+/**
+ * Selects the properties of `Target` to cache: `true` for a value, a nested object for a child object.
+ */
+export type CachedApiProps<Target = any> = {
+  [K in keyof Target]?: boolean | (NonNullable<Target[K]> extends object ? CachedApiProps<NonNullable<Target[K]>> : never);
+};
+
+/**
+ * A value that has a subset of the properties of `Target`, recursively.
+ */
+type Subset<Target> = { [K in keyof Target]?: Subset<NonNullable<Target[K]>> };
+
+/**
+ * Wraps the properties of the object returned by `getTarget` flagged in `props` with getters that
+ * read through to the target once, and serve the cached value until `reset()` is called.
+ */
+export class CachedApiWrapper<Target, T extends Subset<Target> & Record<Exclude<keyof T, keyof Target>, never>> {
+  readonly obj: T;
+  readonly reset: () => void;
+
+  constructor(getTarget: () => Target, props: CachedApiProps<Target>) {
+    const read = (key: string): unknown => (getTarget() as Record<string, unknown> | undefined)?.[key];
+    const wrapper: Record<string, unknown> = {};
+    let data: Record<string, unknown> = {};
+    const children: Array<() => void> = [];
+    Object.entries(props).forEach(([key, value]) => {
+      if (value != null && typeof value === 'object') {
+        const child = new CachedApiWrapper<unknown, Record<string, never>>(() => read(key), value as CachedApiProps);
+        wrapper[key] = child.obj;
+        children.push(child.reset);
+      } else if (value === true) {
+        Object.defineProperty(wrapper, key, {
+          get() {
+            if (!data.hasOwnProperty(key)) {
+              data[key] = read(key);
+            }
+            return data[key];
+          }
+        });
+      }
+    });
+    this.obj = wrapper as T;
+    this.reset = () => {
+      children.forEach(reset => reset());
+      data = {};
+    };
+  }
+}
diff --git a/src/utils/cpm.js b/src/utils/cpm.ts
similarity index 80%
rename from src/utils/cpm.js
rename to src/utils/cpm.ts
index a52cdc45a97..08c4661ff58 100644
--- a/src/utils/cpm.js
+++ b/src/utils/cpm.ts
@@ -7,14 +7,14 @@ import { logError } from '../utils.js';
  * precedence as publisher settings: `getOwn(bidderCode)` wins, otherwise adapter vs bidder depending on
  * `adjustAlternateBids` on the adapter scope.
  */
-export function getBidAdjustmentFn(bid, bs, key, bidRequest) {
+export function getBidAdjustmentFn(bid: any, bs: any, key: string, bidRequest?: any): any {
   const adapterCode = bid?.adapterCode;
   const bidderCode = bid?.bidderCode || bidRequest?.bidder;
   const adjustAlternateBids = bs.get(bid?.adapterCode, 'adjustAlternateBids');
   return bs.getOwn(bidderCode, key) || bs.get(adjustAlternateBids ? adapterCode : bidderCode, key);
 }
 
-export function adjustCpm(cpm, bidResponse, bidRequest, { index = auctionManager.index, bs = bidderSettings } = {}) {
+export function adjustCpm(cpm: number, bidResponse: any, bidRequest?: any, { index = auctionManager.index, bs = bidderSettings }: { index?: any; bs?: any } = {}): number {
   bidRequest = bidRequest || index.getBidRequest(bidResponse);
   const bidCpmAdjustment = getBidAdjustmentFn(bidResponse, bs, 'bidCpmAdjustment', bidRequest);
   if (bidCpmAdjustment && typeof bidCpmAdjustment === 'function') {
diff --git a/src/utils/focusTimeout.js b/src/utils/focusTimeout.ts
similarity index 80%
rename from src/utils/focusTimeout.js
rename to src/utils/focusTimeout.ts
index b448f3d6201..7223e1bff16 100644
--- a/src/utils/focusTimeout.js
+++ b/src/utils/focusTimeout.ts
@@ -1,6 +1,6 @@
-let outOfFocusStart = null; // enforce null otherwise it could be undefined and the callback wouldn't execute
+let outOfFocusStart: number | null = null; // enforce null otherwise it could be undefined and the callback wouldn't execute
 let timeOutOfFocus = 0;
-let suspendedTimeouts = [];
+let suspendedTimeouts: Array<{ callback: () => void; startTime: number; setTimerId: (id: ReturnType<typeof setTimeout>) => void }> = [];
 
 function trackTimeOutOfFocus() {
   if (document.hidden) {
@@ -15,7 +15,7 @@ function trackTimeOutOfFocus() {
 
 document.addEventListener('visibilitychange', trackTimeOutOfFocus);
 
-export function reset() {
+export function reset(): void {
   outOfFocusStart = null;
   timeOutOfFocus = 0;
   suspendedTimeouts = [];
@@ -30,7 +30,7 @@ export function reset() {
  * @param {number} [milliseconds] - Minimum duration (in milliseconds) that the callback will be executed after
  * @returns {function(): number} - Getter function for current timer id
  */
-export function setFocusTimeout(callback, milliseconds) {
+export function setFocusTimeout(callback: () => void, milliseconds?: number): () => ReturnType<typeof setTimeout> {
   const startTime = timeOutOfFocus;
   let timerId = setTimeout(() => {
     if (timeOutOfFocus === startTime && outOfFocusStart == null) {
diff --git a/src/utils/gdpr.js b/src/utils/gdpr.ts
similarity index 67%
rename from src/utils/gdpr.js
rename to src/utils/gdpr.ts
index 6151861a67b..3cce0663ed8 100644
--- a/src/utils/gdpr.js
+++ b/src/utils/gdpr.ts
@@ -4,7 +4,7 @@
  * @param gdprConsent GDPR consent data
  * @returns {boolean} true if the gdprConsent is null-y; or GDPR does not apply; or if purpose 1 consent was given.
  */
-export function hasPurpose1Consent(gdprConsent) {
+export function hasPurpose1Consent(gdprConsent?: { gdprApplies?: boolean; vendorData?: { purpose?: { consents?: Record<number, boolean> } } } | null): boolean {
   if (gdprConsent?.gdprApplies) {
     return gdprConsent?.vendorData?.purpose?.consents?.[1] === true;
   }
diff --git a/src/utils/ipUtils.js b/src/utils/ipUtils.ts
similarity index 83%
rename from src/utils/ipUtils.js
rename to src/utils/ipUtils.ts
index cbb0c38c298..1f5c6a7c600 100644
--- a/src/utils/ipUtils.js
+++ b/src/utils/ipUtils.ts
@@ -1,4 +1,4 @@
-export function scrubIPv4(ip) {
+export function scrubIPv4(ip?: string | null): string | null {
   if (!ip) {
     return null;
   }
@@ -11,7 +11,7 @@ export function scrubIPv4(ip) {
     return null;
   }
 
-  const mask = [];
+  const mask: number[] = [];
   for (let i = 0; i < 4; i++) {
     const n = Math.max(0, Math.min(8, ones - (i * 8)));
     mask.push((0xff << (8 - n)) & 0xff);
@@ -22,7 +22,7 @@ export function scrubIPv4(ip) {
   return maskedIP.join('.');
 }
 
-export function scrubIPv6(ip) {
+export function scrubIPv6(ip?: string | null): string | null {
   if (!ip) {
     return null;
   }
@@ -40,7 +40,7 @@ export function scrubIPv6(ip) {
     return null;
   }
 
-  const mask = [];
+  const mask: number[] = [];
   for (let i = 0; i < 8; i++) {
     const n = Math.max(0, Math.min(16, ones - (i * 16)));
     mask.push((0xffff << (16 - n)) & 0xffff);
diff --git a/src/utils/objects.ts b/src/utils/objects.ts
index abb12f6cbd1..e2d58b22179 100644
--- a/src/utils/objects.ts
+++ b/src/utils/objects.ts
@@ -25,35 +25,35 @@ const toString = Object.prototype.toString;
  * Return if the object is of the
  * given type.
  */
-export function isFn(object): object is AnyFunction {
-  return typeof object === 'function';
+export function isFn(value: unknown): value is AnyFunction {
+  return typeof value === 'function';
 }
 
-export function isStr(object): object is string {
-  return typeof object === 'string';
+export function isStr(value: unknown): value is string {
+  return typeof value === 'string';
 }
 
-export const isArray: (object) => object is any[] = Array.isArray.bind(Array);
+export const isArray: (value: unknown) => value is any[] = Array.isArray.bind(Array);
 
-export function isNumber(object): object is number {
-  return typeof object === 'number';
+export function isNumber(value: unknown): value is number {
+  return typeof value === 'number';
 }
 
-export function isPlainObject(object): object is Record<any, unknown> {
-  return toString.call(object) === '[object Object]';
+export function isPlainObject(value: unknown): value is Record<any, any> {
+  return toString.call(value) === '[object Object]';
 }
 
-export function isBoolean(object): object is boolean {
-  return typeof object === 'boolean';
+export function isBoolean(value: unknown): value is boolean {
+  return typeof value === 'boolean';
 }
 
 /**
  * Checks input is integer or not
  * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isInteger
  */
-export const isInteger: (value) => value is number = Number.isInteger.bind(Number);
+export const isInteger: (value: unknown) => value is number = Number.isInteger.bind(Number);
 
-export function isArrayOfNums<L extends number>(val, size?: L): val is Repeat<number, L> {
+export function isArrayOfNums<L extends number>(val: unknown, size?: L): val is Repeat<number, L> {
   // Array.from because every() skips holes in sparse arrays
   return (isArray(val)) && ((size) ? val.length === size : true) && (Array.from(val).every(v => isInteger(v)));
 }
@@ -62,7 +62,7 @@ export function isArrayOfNums<L extends number>(val, size?: L): val is Repeat<nu
  * Normalize a single size `[w, h]` or an array of sizes `[[w, h], ...]` into an array of sizes.
  * Returns an empty array if the input is invalid, or (when `targLength` is given) does not have exactly that many elements.
  */
-export function validateSizes(sizes, targLength?: number): Size[] {
+export function validateSizes(sizes: unknown, targLength?: number): Size[] {
   if (isArray(sizes) && ((targLength) ? sizes.length === targLength : sizes.length > 0)) {
     // Array.from because every() skips holes in sparse arrays
     if (Array.from(sizes).every(sz => isArrayOfNums(sz, 2))) {
diff --git a/src/utils/reducers.js b/src/utils/reducers.ts
similarity index 65%
rename from src/utils/reducers.js
rename to src/utils/reducers.ts
index 97102dadf57..8ae395e57fa 100644
--- a/src/utils/reducers.js
+++ b/src/utils/reducers.ts
@@ -1,19 +1,22 @@
+import type { Bid } from '../bidfactory.ts';
 import { DEFAULT_PRIORITY, PRIORITY_INCREMENT } from './desirability.js';
 
-export function simpleCompare(a, b) {
+export type Compare<T> = (a: T, b: T) => number;
+
+export function simpleCompare<T>(a: T, b: T): number {
   if (a === b) return 0;
   return a < b ? -1 : 1;
 }
 
-export function keyCompare(key = (item) => item) {
+export function keyCompare<T>(key: (item: T) => unknown = (item) => item): Compare<T> {
   return (a, b) => simpleCompare(key(a), key(b));
 }
 
-export function reverseCompare(compare = simpleCompare) {
+export function reverseCompare<T>(compare: Compare<T> = simpleCompare): Compare<T> {
   return (a, b) => -compare(a, b) || 0;
 }
 
-export function tiebreakCompare(...compares) {
+export function tiebreakCompare<T>(...compares: Array<Compare<T>>): Compare<T> {
   return function (a, b) {
     for (const cmp of compares) {
       const val = cmp(a, b);
@@ -23,28 +26,28 @@ export function tiebreakCompare(...compares) {
   };
 }
 
-export function minimum(compare = simpleCompare) {
+export function minimum<T>(compare: Compare<T> = simpleCompare): (min: T, item: T) => T {
   return (min, item) => compare(item, min) < 0 ? item : min;
 }
 
-export function maximum(compare = simpleCompare) {
+export function maximum<T>(compare: Compare<T> = simpleCompare): (min: T, item: T) => T {
   return minimum(reverseCompare(compare));
 }
 
-const cpmCompare = keyCompare((bid) => bid.cpm);
-const timestampCompare = keyCompare((bid) => bid.responseTimestamp);
+const cpmCompare = keyCompare<Bid>((bid) => bid.cpm);
+const timestampCompare = keyCompare<Bid>((bid) => bid.responseTimestamp);
 
 // This function will get highest cpm value bid, in case of tie it will return the bid with lowest timeToRespond
-export const getHighestCpm = maximum(tiebreakCompare(cpmCompare, reverseCompare(keyCompare((bid) => bid.timeToRespond))));
+export const getHighestCpm = maximum(tiebreakCompare(cpmCompare, reverseCompare(keyCompare<Bid>((bid) => bid.timeToRespond))));
 
-export function priorityCompare(left, right) {
+export function priorityCompare(left: any, right: any): number {
   const a = left.priority ?? DEFAULT_PRIORITY;
   const b = right.priority ?? DEFAULT_PRIORITY;
   if (a === b) return 0;
   return a < b ? -PRIORITY_INCREMENT : PRIORITY_INCREMENT;
 }
 
-export function dealsFirst(a, b) {
+export function dealsFirst(a: any, b: any): number {
   if (a.adserverTargeting.hb_deal !== undefined && b.adserverTargeting.hb_deal === undefined) {
     return -1;
   }
@@ -54,7 +57,7 @@ export function dealsFirst(a, b) {
   return 0;
 }
 
-export const bidDesirabilityCompare = tiebreakCompare(priorityCompare, keyCompare((bid) => bid.desirability ?? bid.cpm));
+export const bidDesirabilityCompare = tiebreakCompare<Bid>(priorityCompare, keyCompare<Bid>((bid) => bid.desirability ?? bid.cpm));
 
 // Sort comparator that orders bids by `.desirability` (falling back to cpm), highest first.
 export const highestDesirabilityFirst = reverseCompare(bidDesirabilityCompare);
@@ -62,7 +65,7 @@ export const highestDesirabilityFirst = reverseCompare(bidDesirabilityCompare);
 // This function will get highest bid by `.desirability` (publisher `bidDesirabilityAdjustment` when set, else mirrors cpm via `adjustBids`);
 // ties use lowest `timeToRespond`, matching {@link getHighestCpm}.
 export const getHighestDesirability = maximum(
-  tiebreakCompare(bidDesirabilityCompare, reverseCompare(keyCompare((bid) => bid.timeToRespond)))
+  tiebreakCompare<Bid>(bidDesirabilityCompare, reverseCompare(keyCompare<Bid>((bid) => bid.timeToRespond)))
 );
 
 // This function will get the oldest highest cpm value bid, in case of tie it will return the bid which came in first
diff --git a/src/utils/winDimensions.js b/src/utils/winDimensions.ts
similarity index 74%
rename from src/utils/winDimensions.js
rename to src/utils/winDimensions.ts
index 83bc6a0f300..c824da9dfc1 100644
--- a/src/utils/winDimensions.js
+++ b/src/utils/winDimensions.ts
@@ -2,7 +2,20 @@ import { canAccessWindowTop, internal as utilsInternals } from '../utils.js';
 import { CachedApiWrapper } from './cachedApiWrapper.js';
 import { endLayoutEpoch, onLayoutEpochEnd, startLayoutEpoch } from './layoutEpoch.js';
 
-const winDimensions = new CachedApiWrapper(
+export type WinDimensions = {
+  innerHeight: number;
+  innerWidth: number;
+  scrollX: number;
+  scrollY: number;
+  screen: { width: number; height: number };
+  visualViewport: { width: number; height: number };
+  document: {
+    documentElement: { clientWidth: number; clientHeight: number; scrollTop: number; scrollLeft: number };
+    body: { scrollTop: number; scrollLeft: number; clientWidth: number; clientHeight: number };
+  };
+};
+
+const winDimensions = new CachedApiWrapper<Window, WinDimensions>(
   () => {
     // called for every value read into the cache, including through an object obtained from
     // getWinDimensions() in an earlier epoch, so that each value is discarded when the epoch it was read in ends
@@ -48,9 +61,9 @@ onLayoutEpochEnd(() => internal.winDimensions.reset());
 /**
  * Dimensions and scroll offsets of the top window (or of this window, if the top one is not accessible).
  * Values are cached for the current layout epoch, together with element rects from the
- * `boundingClientRect` library, so the two can be combined; see `layoutEpoch.js`.
+ * `boundingClientRect` library, so the two can be combined; see `layoutEpoch.ts`.
  */
-export function getWinDimensions() {
+export function getWinDimensions(): WinDimensions {
   return internal.winDimensions.obj;
 }
 
@@ -58,7 +71,7 @@ export function resetWinDimensions() {
   endLayoutEpoch();
 }
 
-export function getScreenOrientation(win) {
+export function getScreenOrientation(win?: Window): 'portrait' | 'landscape' | undefined {
   const fallbackWin = win ?? (canAccessWindowTop() ? utilsInternals.getWindowTop() : utilsInternals.getWindowSelf());
   const screenData = fallbackWin?.screen ?? utilsInternals.getWindowSelf()?.screen ?? window?.screen;
   const width = Number(screenData?.width);