diff --git a/.config/example.yml b/.config/example.yml
index f3caa0d676..08a5680c41 100644
--- a/.config/example.yml
+++ b/.config/example.yml
@@ -425,3 +425,11 @@ attachLdSignatureForRelays: true
 # If you're not using jemalloc, this may cause memory fragmentation and performance issues! (https://www.npmjs.com/package/ws#websocket-compression)
 # jemalloc is used by default in the Sharkey Docker image and may be set up manually otherwise: https://github.com/jemalloc/jemalloc/wiki/getting-started
 websocketCompression: false
+
+# Inject arbitrary HTML tags to customize Sharkey without having to fork it
+#customHtml:
+#  head: |
+#    <!-- The possibilities are limitless! -->
+#    <script>console.log("Hello, world!")</script>
+#    <style>.whatever { color: red; }</style>
+#    <link rel="stylesheet" href="https://example.com/styles.css">
diff --git a/packages/backend/src/config.ts b/packages/backend/src/config.ts
index 067672fd79..9bbd50cac5 100644
--- a/packages/backend/src/config.ts
+++ b/packages/backend/src/config.ts
@@ -138,6 +138,10 @@ type Source = {
 	};
 
 	websocketCompression?: boolean;
+
+	customHtml?: {
+		head?: string;
+	}
 };
 
 export type Config = {
@@ -257,6 +261,10 @@ export type Config = {
 	};
 
 	websocketCompression?: boolean;
+
+	customHtml: {
+		head: string;
+	}
 };
 
 export type FulltextSearchProvider = 'sqlLike' | 'sqlPgroonga' | 'meilisearch' | 'sqlTsvector';
@@ -406,6 +414,9 @@ export function loadConfig(): Config {
 			maxAge: config.activityLogging?.maxAge ?? (1000 * 60 * 60 * 24 * 30),
 		},
 		websocketCompression: config.websocketCompression ?? false,
+		customHtml: {
+			head: config.customHtml?.head ?? '',
+		},
 	};
 }
 
@@ -558,4 +569,5 @@ function applyEnvOverrides(config: Source) {
 	_apply_top([['signToActivityPubGet', 'checkActivityPubGetSignature', 'setupPassword']]);
 	_apply_top(['logging', 'sql', ['disableQueryTruncation', 'enableQueryParamLogging']]);
 	_apply_top(['activityLogging', ['enabled', 'preSave', 'maxAge']]);
+	_apply_top(['customHtml', ['head']]);
 }
diff --git a/packages/backend/src/server/web/ClientServerService.ts b/packages/backend/src/server/web/ClientServerService.ts
index 3ed811e737..437a6802b8 100644
--- a/packages/backend/src/server/web/ClientServerService.ts
+++ b/packages/backend/src/server/web/ClientServerService.ts
@@ -521,6 +521,7 @@ export class ClientServerService {
 				url: this.config.url,
 				title: this.meta.name ?? 'Sharkey',
 				desc: this.meta.description,
+				customHead: this.config.customHtml.head,
 				...await this.generateCommonPugData(this.meta),
 				...data,
 			});
diff --git a/packages/backend/src/server/web/views/base.pug b/packages/backend/src/server/web/views/base.pug
index f57dbbbf4e..f7b0377b22 100644
--- a/packages/backend/src/server/web/views/base.pug
+++ b/packages/backend/src/server/web/views/base.pug
@@ -45,6 +45,8 @@ html
 		link(rel='stylesheet' href=`/static-assets/fonts/sharkey-icons/style.css?version=${version}`)
 		link(rel='modulepreload' href=`/vite/${entry.file}`)
 
+		| !{customHead}
+
 		if !config.frontendManifestExists
 				script(type="module" src="/vite/@vite/client")