diff --git a/.changeset/itchy-mangos-wink.md b/.changeset/itchy-mangos-wink.md
new file mode 100644
index 000000000..bbbfde7db
--- /dev/null
+++ b/.changeset/itchy-mangos-wink.md
@@ -0,0 +1,6 @@
+---
+'@verdaccio/middleware': patch
+'@verdaccio/url': patch
+---
+
+Improved TS types for renderHTML() and related functions (by @tobbe in #4605)
diff --git a/packages/core/url/src/index.ts b/packages/core/url/src/index.ts
index bec367dbe..e7dc79942 100644
--- a/packages/core/url/src/index.ts
+++ b/packages/core/url/src/index.ts
@@ -1,4 +1,5 @@
 import buildDebug from 'debug';
+import type { IncomingHttpHeaders } from 'node:http';
 import { URL } from 'url';
 import validator from 'validator';
 
@@ -31,7 +32,7 @@ export function isHost(url: string = '', options = {}): boolean {
 /**
  * Detect running protocol (http or https)
  */
-export function getWebProtocol(headerProtocol: string | void, protocol: string): string {
+export function getWebProtocol(headerProtocol: string | undefined, protocol: string): string {
   let returnProtocol;
   const [, defaultProtocol] = validProtocols;
   // HAProxy variant might return http,http with X-Forwarded-Proto
@@ -101,7 +102,7 @@ export type RequestOptions = {
   /**
    * Request headers.
    */
-  headers: { [key: string]: string };
+  headers: IncomingHttpHeaders;
   remoteAddress?: string;
   /**
    * Logged username the request, usually after token verification.
@@ -119,10 +120,13 @@ export function getPublicUrl(url_prefix: string = '', requestOptions: RequestOpt
     if (!isHost(host)) {
       throw new Error('invalid host');
     }
-    const protoHeader =
+
+    const protoHeader: string =
       process.env.VERDACCIO_FORWARDED_PROTO?.toLocaleLowerCase() ??
       HEADERS.FORWARDED_PROTO.toLowerCase();
-    const protocol = getWebProtocol(requestOptions.headers[protoHeader], requestOptions.protocol);
+    const forwardedProtocolHeaderValue = requestOptions.headers[protoHeader] as string | undefined;
+
+    const protocol = getWebProtocol(forwardedProtocolHeaderValue, requestOptions.protocol);
     const combinedUrl = combineBaseUrl(protocol, host, url_prefix);
     debug('public url by request %o', combinedUrl);
     return combinedUrl;
diff --git a/packages/middleware/src/middlewares/web/utils/renderHTML.ts b/packages/middleware/src/middlewares/web/utils/renderHTML.ts
index a2f96c46a..a36b0f89a 100644
--- a/packages/middleware/src/middlewares/web/utils/renderHTML.ts
+++ b/packages/middleware/src/middlewares/web/utils/renderHTML.ts
@@ -1,4 +1,5 @@
 import buildDebug from 'debug';
+import type { Response } from 'express';
 import LRU from 'lru-cache';
 import path from 'path';
 import { URL } from 'url';
@@ -6,10 +7,12 @@ import { URL } from 'url';
 import { WEB_TITLE } from '@verdaccio/config';
 import { HEADERS } from '@verdaccio/core';
 import { ConfigYaml, TemplateUIOptions } from '@verdaccio/types';
-import { isURLhasValidProtocol } from '@verdaccio/url';
-import { getPublicUrl } from '@verdaccio/url';
+import type { RequestOptions } from '@verdaccio/url';
+import { getPublicUrl, isURLhasValidProtocol } from '@verdaccio/url';
 
+import type { Manifest } from './manifest';
 import renderTemplate from './template';
+import type { WebpackManifest } from './template';
 import { hasLogin, validatePrimaryColor } from './web-utils';
 
 const DEFAULT_LANGUAGE = 'es-US';
@@ -17,19 +20,20 @@ const cache = new LRU({ max: 500, ttl: 1000 * 60 * 60 });
 
 const debug = buildDebug('verdaccio:web:render');
 
-const defaultManifestFiles = {
+const defaultManifestFiles: Manifest = {
   js: ['runtime.js', 'vendors.js', 'main.js'],
   ico: 'favicon.ico',
+  css: [],
 };
 
-export function resolveLogo(config: ConfigYaml, req) {
+export function resolveLogo(config: ConfigYaml, requestOptions: RequestOptions) {
   if (typeof config?.web?.logo !== 'string') {
     return '';
   }
   const isLocalFile = config?.web?.logo && !isURLhasValidProtocol(config?.web?.logo);
 
   if (isLocalFile) {
-    return `${getPublicUrl(config?.url_prefix, req)}-/static/${path.basename(config?.web?.logo)}`;
+    return `${getPublicUrl(config?.url_prefix, requestOptions)}-/static/${path.basename(config?.web?.logo)}`;
   } else if (isURLhasValidProtocol(config?.web?.logo)) {
     return config?.web?.logo;
   } else {
@@ -37,9 +41,15 @@ export function resolveLogo(config: ConfigYaml, req) {
   }
 }
 
-export default function renderHTML(config: ConfigYaml, manifest, manifestFiles, req, res) {
+export default function renderHTML(
+  config: ConfigYaml,
+  manifest: WebpackManifest,
+  manifestFiles: Manifest | null | undefined,
+  requestOptions: RequestOptions,
+  res: Response
+) {
   const { url_prefix } = config;
-  const base = getPublicUrl(config?.url_prefix, req);
+  const base = getPublicUrl(config?.url_prefix, requestOptions);
   const basename = new URL(base).pathname;
   const language = config?.i18n?.web ?? DEFAULT_LANGUAGE;
   const hideDeprecatedVersions = config?.web?.hideDeprecatedVersions ?? false;
@@ -51,7 +61,7 @@ export default function renderHTML(config: ConfigYaml, manifest, manifestFiles,
   const title = config?.web?.title ?? WEB_TITLE;
   const login = hasLogin(config);
   const scope = config?.web?.scope ?? '';
-  const logo = resolveLogo(config, req);
+  const logo = resolveLogo(config, requestOptions);
   const pkgManagers = config?.web?.pkgManagers ?? ['yarn', 'pnpm', 'npm'];
   const version = res.locals.app_version ?? '';
   const flags = {