diff --git a/src/album.ts b/src/album.ts
index 9cac6e3..6549208 100644
--- a/src/album.ts
+++ b/src/album.ts
@@ -1,60 +1,144 @@
 import { LastFM } from './base';
-import { LastFMParam, LastFMApiRequest, LastFMRequestParams, LastFMUnknownFunction } from './api-request';
+import {
+	LastFMParam,
+	LastFMApiRequest,
+	LastFMBooleanNumber,
+	LastFMRequestParams,
+	LastFMUnknownFunction,
+	LastFMBooleanNumberOrVoid
+} from './api-request';
 
-export interface LastFMAlbumParams {
-	readonly album: string;
-	readonly artist: string;
-}
+export type LastFMAlbumParams = Readonly<{
+	album: string;
+	artist: string;
+}>;
 
-export interface LastFMAlbumOptionalParams {
-	readonly mbid?: string;
-	readonly autocorrect?: 0 | 1;
-}
+export type LastFMAlbumOptionalParams = Readonly<{
+	mbid?: string;
+	autocorrect?: LastFMBooleanNumber;
+}>;
 
-export interface LastFMAlbumAddTagsParams extends LastFMRequestParams<LastFMParam>, LastFMAlbumParams {
-	readonly tags: string | string[];
-}
+export type LastFMAlbumAddTagsParams = LastFMRequestParams<LastFMParam> &
+	LastFMAlbumParams &
+	Readonly<{
+		tags: string | string[];
+	}>;
 
-export interface LastFMAlbumGetInfoParams
-	extends LastFMRequestParams<0 | 1 | void>,
-		LastFMAlbumParams,
-		LastFMAlbumOptionalParams {
-	readonly lang?: string;
-	readonly username?: string;
-}
+export type LastFMAlbumGetInfoParams = LastFMRequestParams<LastFMBooleanNumberOrVoid> &
+	LastFMAlbumParams &
+	LastFMAlbumOptionalParams &
+	Readonly<{
+		lang?: string;
+		username?: string;
+	}>;
 
-export interface LastFMAlbumGetTagsParams
-	extends LastFMRequestParams<0 | 1 | void>,
-		LastFMAlbumParams,
-		LastFMAlbumOptionalParams {
-	readonly user?: string;
-}
+export type LastFMAlbumGetTagsParams = LastFMRequestParams<LastFMBooleanNumberOrVoid> &
+	LastFMAlbumParams &
+	LastFMAlbumOptionalParams &
+	Readonly<{
+		user?: string;
+	}>;
 
-export interface LastFMAlbumGetTopTagsParams
-	extends LastFMRequestParams<0 | 1 | void>,
-		LastFMAlbumParams,
-		LastFMAlbumOptionalParams {}
+export type LastFMAlbumGetTopTagsParams = LastFMRequestParams<LastFMBooleanNumberOrVoid> &
+	LastFMAlbumParams &
+	LastFMAlbumOptionalParams;
 
-export interface LastFMAlbumRemoveLastFMTagParams extends LastFMRequestParams<LastFMParam>, LastFMAlbumParams {
-	readonly tag: string;
-}
+export type LastFMAlbumRemoveLastFMTagParams = LastFMRequestParams<LastFMParam> &
+	LastFMAlbumParams &
+	Readonly<{
+		tag: string;
+	}>;
 
-export interface LastFMAlbumSearchParams extends LastFMRequestParams<number | void> {
-	readonly page?: number;
-	readonly album: string;
-	readonly limit?: number;
-}
+export type LastFMAlbumSearchParams = LastFMRequestParams<number | void> &
+	Readonly<{
+		page?: number;
+		album: string;
+		limit?: number;
+	}>;
 
-export class LastFMAlbum extends LastFM {
-	constructor(apiKey: string, secret?: string, sessionKey?: string) {
-		super(apiKey, secret, sessionKey);
-	}
+export type LastFMAlbumGetInfoResponse = Readonly<{
+	album: {
+		artist: string;
+		mbid: string;
+		tags: {
+			tag: Array<{
+				url: string;
+				name: string;
+			}>;
+		};
+		playcount: string;
+		image: Array<{
+			size: string;
+			'#text': string;
+		}>;
+		tracks: {
+			track: Array<{
+				streamable: { fulltrack: string; '#text': string };
+				duration: number;
+				url: string;
+				name: string;
+				'@attr': {
+					rank: number;
+				};
+				artist: {
+					url: string;
+					name: string;
+					mbid: string;
+				};
+			}>;
+		};
+		url: string;
+		name: string;
+		listeners: string;
+		wiki: {
+			published: string;
+			summary: string;
+		};
+	};
+}>;
 
-	public addTags(
-		params: LastFMAlbumAddTagsParams,
-		callback: LastFMUnknownFunction
-	): Promise<LastFMApiRequest> | void {
-		return new LastFMApiRequest()
+export type LastFMAlbumGetTagsResponse = Readonly<{
+	tags: {
+		tag: Array<{
+			name: string;
+			url: string;
+		}>;
+	};
+}>;
+
+export type LastFMAlbumSearchResponse = Readonly<{
+	results: {
+		'opensearch:Query': {
+			'#text': string;
+			role: string;
+			searchTerms: string;
+			startPage: string;
+		};
+		'opensearch:totalResults': string;
+		'opensearch:startIndex': string;
+		'opensearch:itemsPerPage': string;
+		albummatches: {
+			album: Array<{
+				name: string;
+				artist: string;
+				url: string;
+				image: Array<{
+					'#text': string;
+					size: string;
+				}>;
+				streamable: LastFMBooleanNumber;
+				mbid: string;
+			}>;
+		};
+		'@attr': {
+			for: string;
+		};
+	};
+}>;
+
+export class LastFMAlbum extends LastFM {
+	public addTags(params: LastFMAlbumAddTagsParams, callback?: LastFMUnknownFunction): Promise<void> {
+		return new LastFMApiRequest<void>()
 			.set(params)
 			.set({
 				api_key: this.apiKey,
@@ -67,9 +151,9 @@ export class LastFMAlbum extends LastFM {
 
 	public getInfo(
 		params: LastFMAlbumGetInfoParams,
-		callback: LastFMUnknownFunction
-	): Promise<LastFMApiRequest> | void {
-		return new LastFMApiRequest()
+		callback?: LastFMUnknownFunction
+	): Promise<LastFMAlbumGetInfoResponse> {
+		return new LastFMApiRequest<LastFMAlbumGetInfoResponse>()
 			.set(params)
 			.set({
 				api_key: this.apiKey,
@@ -80,9 +164,9 @@ export class LastFMAlbum extends LastFM {
 
 	public getTags(
 		params: LastFMAlbumGetTagsParams,
-		callback: LastFMUnknownFunction
-	): Promise<LastFMApiRequest> | void {
-		return new LastFMApiRequest()
+		callback?: LastFMUnknownFunction
+	): Promise<LastFMAlbumGetTagsResponse> {
+		return new LastFMApiRequest<LastFMAlbumGetTagsResponse>()
 			.set(params)
 			.set({
 				api_key: this.apiKey,
@@ -93,9 +177,9 @@ export class LastFMAlbum extends LastFM {
 
 	public getTopTags(
 		params: LastFMAlbumGetTopTagsParams,
-		callback: LastFMUnknownFunction
-	): Promise<LastFMApiRequest> | void {
-		return new LastFMApiRequest()
+		callback?: LastFMUnknownFunction
+	): Promise<LastFMAlbumGetTagsResponse> {
+		return new LastFMApiRequest<LastFMAlbumGetTagsResponse>()
 			.set(params)
 			.set({
 				api_key: this.apiKey,
@@ -104,11 +188,8 @@ export class LastFMAlbum extends LastFM {
 			.send(callback);
 	}
 
-	public removeTag(
-		params: LastFMAlbumRemoveLastFMTagParams,
-		callback: LastFMUnknownFunction
-	): Promise<LastFMApiRequest> | void {
-		return new LastFMApiRequest()
+	public removeTag(params: LastFMAlbumRemoveLastFMTagParams, callback?: LastFMUnknownFunction): Promise<void> {
+		return new LastFMApiRequest<void>()
 			.set(params)
 			.set({
 				api_key: this.apiKey,
@@ -119,8 +200,11 @@ export class LastFMAlbum extends LastFM {
 			.send('POST', callback);
 	}
 
-	public search(params: LastFMAlbumSearchParams, callback: LastFMUnknownFunction): Promise<LastFMApiRequest> | void {
-		return new LastFMApiRequest()
+	public search(
+		params: LastFMAlbumSearchParams,
+		callback?: LastFMUnknownFunction
+	): Promise<LastFMAlbumSearchResponse> {
+		return new LastFMApiRequest<LastFMAlbumSearchResponse>()
 			.set(params)
 			.set({
 				api_key: this.apiKey,
diff --git a/src/api-request.ts b/src/api-request.ts
index 2040d9c..4a8bb5d 100644
--- a/src/api-request.ts
+++ b/src/api-request.ts
@@ -2,19 +2,22 @@ import { createHash } from 'crypto';
 import { parse, stringify } from 'querystring';
 import { request, RequestOptions } from 'https';
 
-export type LastFMUnknownFunction = (...args: unknown[]) => unknown;
 export type LastFMParam = string | string[];
 export type LastFMParams<T> = Record<string, LastFMParam | T>;
+export type LastFMVoidOrNumber = void | number;
+export type LastFMBooleanNumber = 0 | 1;
+export type LastFMUnknownFunction = (...args: unknown[]) => unknown;
 export type LastFMRequestParams<T> = Record<string, LastFMParam | T>;
+export type LastFMBooleanNumberOrVoid = LastFMBooleanNumber | void;
 
-export class LastFMApiRequest {
+export class LastFMApiRequest<T> {
 	private params: Map<string, any> = new Map();
 
 	constructor() {
 		this.params.set('format', 'json');
 	}
 
-	public set<T>(params: LastFMParams<void | T>): LastFMApiRequest {
+	public set<P>(params: LastFMParams<void | P>): this {
 		Object.entries(params).forEach(([key, value]) => {
 			if (typeof value !== 'undefined') {
 				this.params.set(key, value);
@@ -24,7 +27,7 @@ export class LastFMApiRequest {
 		return this;
 	}
 
-	public sign(secret?: string): LastFMApiRequest {
+	public sign(secret?: string): this {
 		const paramsObj: LastFMParams<string> = this.setParams();
 		const paramsObjParsed = parse(stringify(paramsObj));
 
@@ -59,10 +62,7 @@ export class LastFMApiRequest {
 		return this;
 	}
 
-	public send(
-		method?: string | LastFMUnknownFunction,
-		callback?: LastFMUnknownFunction
-	): void | Promise<LastFMApiRequest> {
+	public send(method?: string | LastFMUnknownFunction, callback?: LastFMUnknownFunction): Promise<T> {
 		callback =
 			callback === undefined
 				? typeof method === 'function'
@@ -71,6 +71,7 @@ export class LastFMApiRequest {
 				: typeof callback === 'function'
 				? callback
 				: undefined;
+
 		method = typeof method === 'string' ? method : undefined;
 
 		if (this.params.has('callback')) {
@@ -129,12 +130,10 @@ export class LastFMApiRequest {
 		});
 
 		if (callback && typeof callback === 'function') {
-			LastFMapiRequest.then(
+			return LastFMapiRequest.then(
 				data => callback!(null, data),
 				err => callback!(err, null)
-			);
-
-			return undefined;
+			) as typeof LastFMapiRequest;
 		}
 
 		return LastFMapiRequest;