diff --git a/neko/index.js b/neko/index.js
index 31eade4ac..b25acfb60 100644
--- a/neko/index.js
+++ b/neko/index.js
@@ -295,7 +295,7 @@ if (!nativeBinding) {
   throw new Error(`Failed to load native binding`)
 }
 
-const { EnvConfig, readEnvironmentConfig, readServerConfig, JsDbConn, connectToDatabase, AntennaSrcEnum, MutedNoteReasonEnum, NoteVisibilityEnum, NotificationTypeEnum, PageVisibilityEnum, PollNotevisibilityEnum, RelayStatusEnum, UserEmojimodpermEnum, UserProfileFfvisibilityEnum, UserProfileMutingnotificationtypesEnum, stringToAcct, acctToString, getFullApAccount, isSelfHost, extractHost, toPuny, toPunyOptional, convertToHiddenPost, sqlLikeEscape, safeForSql, formatMilliseconds, nativeInitIdGenerator, nativeCreateId, nativeGetTimestamp, fetchMeta, metaToPugArgs, hasOtherRenoteOfThisNote, genString, IdConvertType, convertId } = nativeBinding
+const { EnvConfig, readEnvironmentConfig, readServerConfig, JsDbConn, connectToDatabase, AntennaSrcEnum, MutedNoteReasonEnum, NoteVisibilityEnum, NotificationTypeEnum, PageVisibilityEnum, PollNotevisibilityEnum, RelayStatusEnum, UserEmojimodpermEnum, UserProfileFfvisibilityEnum, UserProfileMutingnotificationtypesEnum, stringToAcct, acctToString, getFullApAccount, isSelfHost, extractHost, toPuny, toPunyOptional, convertToHiddenPost, sqlLikeEscape, safeForSql, formatMilliseconds, nativeInitIdGenerator, nativeCreateId, nativeGetTimestamp, fetchMeta, metaToPugArgs, hasOtherRenoteOfThisNote, nyaify, genString, IdConvertType, convertId } = nativeBinding
 
 module.exports.EnvConfig = EnvConfig
 module.exports.readEnvironmentConfig = readEnvironmentConfig
@@ -329,6 +329,7 @@ module.exports.nativeGetTimestamp = nativeGetTimestamp
 module.exports.fetchMeta = fetchMeta
 module.exports.metaToPugArgs = metaToPugArgs
 module.exports.hasOtherRenoteOfThisNote = hasOtherRenoteOfThisNote
+module.exports.nyaify = nyaify
 module.exports.genString = genString
 module.exports.IdConvertType = IdConvertType
 module.exports.convertId = convertId
diff --git a/packages/backend-rs/Cargo.lock b/packages/backend-rs/Cargo.lock
index 7c939254a..4e6fea190 100644
--- a/packages/backend-rs/Cargo.lock
+++ b/packages/backend-rs/Cargo.lock
@@ -214,6 +214,7 @@ dependencies = [
  "parse-display",
  "pretty_assertions",
  "rand",
+ "regex",
  "schemars",
  "sea-orm",
  "serde",
diff --git a/packages/backend-rs/Cargo.toml b/packages/backend-rs/Cargo.toml
index 4bab77cdc..1c2b5ef5e 100644
--- a/packages/backend-rs/Cargo.toml
+++ b/packages/backend-rs/Cargo.toml
@@ -20,6 +20,7 @@ jsonschema = "0.17.1"
 once_cell = "1.19.0"
 parse-display = "0.8.2"
 rand = "0.8.5"
+regex = "1.10.3"
 schemars = { version = "0.8.16", features = ["chrono"] }
 sea-orm = { version = "0.12.12", features = ["sqlx-postgres", "runtime-tokio-rustls"] }
 serde = { version = "1.0.195", features = ["derive"] }
diff --git a/packages/backend-rs/src/util/mod.rs b/packages/backend-rs/src/util/mod.rs
index e4c63fa07..50fab5e07 100644
--- a/packages/backend-rs/src/util/mod.rs
+++ b/packages/backend-rs/src/util/mod.rs
@@ -6,4 +6,5 @@ pub mod format_milliseconds;
 pub mod id;
 pub mod meta;
 pub mod note;
+pub mod nyaify;
 pub mod random;
diff --git a/packages/backend-rs/src/util/nyaify.rs b/packages/backend-rs/src/util/nyaify.rs
new file mode 100644
index 000000000..48b0f0cd0
--- /dev/null
+++ b/packages/backend-rs/src/util/nyaify.rs
@@ -0,0 +1,84 @@
+use once_cell::sync::Lazy;
+use regex::{Captures, Regex};
+
+#[napi_derive::napi]
+pub fn nyaify(text: String, lang: Option<String>, append_miao: bool) -> String {
+    let mut to_return = text.clone();
+
+    {
+        static RE: Lazy<Regex> =
+            Lazy::new(|| Regex::new(r"(?i-u)(non)([bcdfghjklmnpqrstvwxyz])").unwrap());
+        to_return = RE
+            .replace_all(&to_return, |caps: &Captures<'_>| {
+                format!(
+                    "{}{}",
+                    match &caps[1] {
+                        "non" => "nyan",
+                        "Non" => "Nyan",
+                        "NON" => "NYAN",
+                        _ => &caps[1],
+                    },
+                    &caps[2]
+                )
+            })
+            .to_string();
+    }
+
+    {
+        static RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"다([.．。…?？!！\s]|$)").unwrap());
+        to_return = RE.replace_all(&to_return, r"다냥$1").to_string();
+    }
+
+    {
+        static RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"야([?？\s]|$)").unwrap());
+        to_return = RE.replace_all(&to_return, r"냥$1").to_string();
+    }
+
+    {
+        static RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"([나-낳])").unwrap());
+        to_return = RE
+            .replace_all(&to_return, |caps: &Captures<'_>| {
+                format!(
+                    "{}",
+                    char::from_u32(
+                        caps[0].chars().next().unwrap() as u32 + 56 /* = '냐' - '나' */
+                    )
+                    .unwrap()
+                )
+            })
+            .to_string();
+    }
+
+    if lang.is_some() && lang.unwrap().starts_with("zh") {
+        static RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"[妙庙描渺瞄秒苗藐廟]").unwrap());
+        to_return = RE.replace_all(&to_return, "喵").to_string();
+    }
+
+    let simple_rules = [
+        ("な", "にゃ"),
+        ("ナ", "ニャ"),
+        ("ﾅ", "ﾆｬ"),
+        ("na", "nya"),
+        ("NA", "NYA"),
+        ("Na", "Nya"),
+        ("morning", "mornyan"),
+        ("Morning", "Mornyan"),
+        ("MORNING", "MORNYAN"),
+        ("everyone", "everynyan"),
+        ("Everyone", "Everynyan"),
+        ("EVERYONE", "EVERYNYAN"),
+        ("να", "νια"),
+        ("ΝΑ", "ΝΙΑ"),
+        ("Να", "Νια"),
+    ];
+
+    simple_rules.into_iter().for_each(|(from, to)| {
+        to_return = to_return.replace(from, to);
+    });
+
+    if append_miao {
+        to_return.push('喵');
+    }
+
+    to_return
+}
diff --git a/packages/backend/src/misc/nyaify.ts b/packages/backend/src/misc/nyaify.ts
deleted file mode 100644
index 37a0bdecd..000000000
--- a/packages/backend/src/misc/nyaify.ts
+++ /dev/null
@@ -1,38 +0,0 @@
-export default function (
-	text: string,
-	lang: string | undefined,
-	appendMiao: boolean,
-): string {
-	text = text
-		// ja-JP
-		.replaceAll("な", "にゃ")
-		.replaceAll("ナ", "ニャ")
-		.replaceAll("ﾅ", "ﾆｬ")
-		// en-US
-		.replaceAll("na", "nya")
-		.replaceAll("Na", "Nya")
-		.replaceAll("NA", "NYA")
-		.replace(/(?<=morn)ing/gi, (x) => (x === "ING" ? "YAN" : "yan"))
-		.replace(/(?<=every)one/gi, (x) => (x === "ONE" ? "NYAN" : "nyan"))
-		.replace(/non(?=[bcdfghjklmnpqrstvwxyz])/gi, (x) =>
-			x === "NON" ? "NYAN" : "nyan",
-		)
-		// ko-KR
-		.replace(/[나-낳]/g, (match) =>
-			String.fromCharCode(
-				match.charCodeAt(0)! + "냐".charCodeAt(0) - "나".charCodeAt(0),
-			),
-		)
-		.replace(/(다$)|(다(?=\.))|(다(?= ))|(다(?=!))|(다(?=\?))/gm, "다냥")
-		.replace(/(야(?=\?))|(야$)|(야(?= ))/gm, "냥")
-		// el-GR
-		.replaceAll("να", "νια")
-		.replaceAll("ΝΑ", "ΝΙΑ")
-		.replaceAll("Να", "Νια");
-
-	// zh-CN, zh-TW
-	if (lang === "zh") text = text.replace(/(妙|庙|描|渺|瞄|秒|苗|藐|廟)/g, "喵");
-	if (appendMiao) text += "喵";
-
-	return text;
-}
diff --git a/packages/backend/src/models/repositories/note.ts b/packages/backend/src/models/repositories/note.ts
index ef9871bc2..0fdf7f96e 100644
--- a/packages/backend/src/models/repositories/note.ts
+++ b/packages/backend/src/models/repositories/note.ts
@@ -12,7 +12,7 @@ import {
 	Channels,
 } from "../index.js";
 import type { Packed } from "@/misc/schema.js";
-import nyaify from "@/misc/nyaify.js";
+import { nyaify } from "backend-rs";
 import { awaitAll } from "@/prelude/await-all.js";
 import { convertReactions, decodeReaction } from "@/misc/reaction-lib.js";
 import type { NoteReaction } from "@/models/entities/note-reaction.js";