diff --git a/src/App.ts b/src/App.ts
index 30636be5..7add9e7f 100644
--- a/src/App.ts
+++ b/src/App.ts
@@ -98,7 +98,7 @@ export abstract class AppBase extends EventEmitter {
   }
 
   abstract _init(options?: AppOptions);
-  loadViews(_viewFilename, _viewName) { }
+  loadViews(_viewFilename, _viewName?) { }
   loadStyles(_filename, _options) { }
 
   component(constructor: ComponentConstructor | SingletonComponentConstructor): this;
diff --git a/src/AppForServer.ts b/src/AppForServer.ts
index a50a75e6..b56e81ab 100644
--- a/src/AppForServer.ts
+++ b/src/AppForServer.ts
@@ -8,12 +8,15 @@
 
 import * as racer from 'racer';
 
-const util = racer.util;
 import { AppBase } from './App';
+import { type DerbyBase } from './Derby';
+import { type StyleCompilerOptions } from './files';
 import { PageForServer } from './PageForServer';
 import parsing = require('./parsing');
 import * as derbyTemplates from './templates';
 
+const util = racer.util;
+
 interface Agent {
   send(message: Record<string, unknown>): void;
 }
@@ -42,7 +45,7 @@ function htmlCompiler(file) {
   return file;
 }
 
-type CompilerFunciton = (file: string, filename?: string, options?: unknown) => unknown;
+type CompilerFunciton = (file: string, filename?: string, options?: unknown) => string;
 
 function watchOnce(filenames, callback) {
   const watcher = chokidar.watch(filenames);
@@ -76,7 +79,7 @@ export class AppForServer extends AppBase {
   watchFiles: boolean;
   router: any;
 
-  constructor(derby, name: string, filename: string, options) {
+  constructor(derby: DerbyBase, name: string, filename: string, options) {
     super(derby, name, filename, options);
     this._init(options);
   }
@@ -208,7 +211,7 @@ export class AppForServer extends AppBase {
     this.scriptMapUrl = (this.scriptMapBaseUrl || serialized.scriptMapBaseUrl) + serialized.scriptMapUrl;
   }
 
-  loadViews(filename, namespace) {
+  loadViews(filename: string, namespace?: string) {
     const data = files.loadViewsSync(this, filename, namespace);
     parsing.registerParsedViews(this, data.views);
     if (this.watchFiles) this._watchViews(data.files, filename, namespace);
@@ -216,7 +219,7 @@ export class AppForServer extends AppBase {
     return this;
   }
 
-  loadStyles(filename, options) {
+  loadStyles(filename: string, options?: StyleCompilerOptions) {
     this._loadStyles(filename, options);
     const stylesView = this.views.find('Styles');
     stylesView.source += '<view is="' + filename + '"></view>';
@@ -224,7 +227,7 @@ export class AppForServer extends AppBase {
     return this;
   }
 
-  private _loadStyles(filename, options) {
+  private _loadStyles(filename: string, options?: StyleCompilerOptions) {
     const styles = files.loadStylesSync(this, filename, options);
 
     let filepath = '';
diff --git a/src/files.ts b/src/files.ts
index 481cc821..d812df69 100644
--- a/src/files.ts
+++ b/src/files.ts
@@ -9,9 +9,10 @@ import * as path from 'node:path';
 import * as racer from 'racer';
 import * as resolve from 'resolve';
 
+import { type AppForServer } from './AppForServer';
 import * as parsing from './parsing';
 
-export function loadViewsSync(app, sourceFilename, namespace) {
+export function loadViewsSync(app: AppForServer, sourceFilename: string, namespace: string) {
   let views = [];
   let files = [];
   const filename = resolve.sync(sourceFilename, {
@@ -43,7 +44,7 @@ export function loadViewsSync(app, sourceFilename, namespace) {
     files = files.concat(imported.files);
   }
 
-  const htmlFile = compiler(file, filename);
+  const htmlFile = compiler(file, filename) as string;
   const parsedViews = parsing.parseViews(htmlFile, namespace, filename, onImport);
   return {
     views: views.concat(parsedViews),
@@ -51,7 +52,11 @@ export function loadViewsSync(app, sourceFilename, namespace) {
   };
 }
 
-export function loadStylesSync(app, sourceFilename, options) {
+export interface StyleCompilerOptions extends Record<string, unknown> {
+  compress?: boolean;
+}
+
+export function loadStylesSync(app: AppForServer, sourceFilename: string, options?: StyleCompilerOptions) {
   if (options == null) {
     options = { compress: racer.util.isProduction };
   }