diff --git a/database/entities/Status.ts b/database/entities/Status.ts
index 4347a453..a7727eee 100644
--- a/database/entities/Status.ts
+++ b/database/entities/Status.ts
@@ -1,3 +1,4 @@
+import { mentionValidator } from "@api";
 import markdownItTaskLists from "@hackmd/markdown-it-task-lists";
 import { dualLogger } from "@loggers";
 import { sanitizeHtml, sanitizeHtmlInline } from "@sanitization";
@@ -365,26 +366,13 @@ export const resolveNote = async (
     return createdNote;
 };
 
-export const createMentionRegExp = () =>
-    createRegExp(
-        exactly("@"),
-        oneOrMore(anyOf(letter.lowercase, digit, charIn("-"))).groupedAs(
-            "username",
-        ),
-        maybe(
-            exactly("@"),
-            oneOrMore(anyOf(letter, digit, charIn("_-.:"))).groupedAs("domain"),
-        ),
-        [global],
-    );
-
 /**
  * Get people mentioned in the content (match @username or @username@domain.com mentions)
  * @param text The text to parse mentions from.
  * @returns An array of users mentioned in the text.
  */
 export const parseTextMentions = async (text: string): Promise<User[]> => {
-    const mentionedPeople = [...text.matchAll(createMentionRegExp())] ?? [];
+    const mentionedPeople = [...text.matchAll(mentionValidator)] ?? [];
     if (mentionedPeople.length === 0) return [];
 
     const baseUrlHost = new URL(config.http.base_url).host;
diff --git a/server/api/well-known/webfinger/index.ts b/server/api/well-known/webfinger/index.ts
index 9742bd61..941e62db 100644
--- a/server/api/well-known/webfinger/index.ts
+++ b/server/api/well-known/webfinger/index.ts
@@ -1,4 +1,9 @@
-import { applyConfig, handleZodError, idValidator } from "@api";
+import {
+    applyConfig,
+    handleZodError,
+    idValidator,
+    webfingerMention,
+} from "@api";
 import { zValidator } from "@hono/zod-validator";
 import { errorResponse, jsonResponse } from "@response";
 import { eq } from "drizzle-orm";
@@ -36,7 +41,7 @@ export default (app: Hono) =>
             const { resource } = context.req.valid("query");
 
             // Check if resource is in the correct format (acct:uuid/username@domain)
-            if (!resource.match(/^acct:[a-zA-Z0-9-]+@[a-zA-Z0-9.-:]+$/)) {
+            if (!resource.match(webfingerMention)) {
                 return errorResponse(
                     "Invalid resource (should be acct:(id or username)@domain)",
                     400,
diff --git a/utils/api.ts b/utils/api.ts
index fc1233f0..57232d98 100644
--- a/utils/api.ts
+++ b/utils/api.ts
@@ -11,7 +11,9 @@ import {
     createRegExp,
     digit,
     exactly,
+    global,
     letter,
+    maybe,
     oneOrMore,
 } from "magic-regexp";
 import { parse } from "qs";
@@ -64,6 +66,28 @@ export const emojiValidatorWithColons = createRegExp(
     [caseInsensitive],
 );
 
+export const mentionValidator = createRegExp(
+    exactly("@"),
+    oneOrMore(anyOf(letter.lowercase, digit, charIn("-"))).groupedAs(
+        "username",
+    ),
+    maybe(
+        exactly("@"),
+        oneOrMore(anyOf(letter, digit, charIn("_-.:"))).groupedAs("domain"),
+    ),
+    [global],
+);
+
+export const webfingerMention = createRegExp(
+    exactly("acct:"),
+    oneOrMore(anyOf(letter, digit, charIn("-"))).groupedAs("username"),
+    maybe(
+        exactly("@"),
+        oneOrMore(anyOf(letter, digit, charIn("_-.:"))).groupedAs("domain"),
+    ),
+    [],
+);
+
 export const handleZodError = (
     result:
         | { success: true; data?: object }