diff --git a/backend/app.ts b/backend/app.ts
index ab23543..1f5fe2a 100644
--- a/backend/app.ts
+++ b/backend/app.ts
@@ -199,14 +199,12 @@ async function handleListFonts(req: Request, res: Response) {
 
 /** GET /api/config — 返回公开配置 */
 async function handleGetConfig(req: Request, res: Response) {
-  const isLlrt = release_name === "llrt";
   return {
     req,
     res: jsonResponse({
       enableTempUpload,
       adminUploadEnabled: !!adminApiKey,
-      /** LLRT 不支持 wasm，无法输出 woff2 */
-      supportedOutTypes: isLlrt ? ["ttf"] : ["woff2", "ttf"],
+      supportedOutTypes: ["woff2", "ttf"],
     }),
   };
 }
@@ -314,12 +312,9 @@ async function handleFontSubset(req: Request, res: Response) {
     };
   }
 
-  /** 默认 ttf（兼容性最好）；LLRT 不支持 wasm 只能用 ttf */
-  const isLlrt = release_name === "llrt";
+  /** 默认 ttf（兼容性最好） */
   const outTypeParam = params.get("outType") || "";
-  const outType = (outTypeParam === "woff2" || outTypeParam === "ttf")
-    ? (isLlrt && outTypeParam === "woff2" ? "ttf" : outTypeParam)
-    : "ttf";
+  const outType = (outTypeParam === "woff2" || outTypeParam === "ttf") ? outTypeParam : "ttf";
 
   const newFont = await fontSubset(oldFontBuffer, text, {
     outType: outType,
diff --git a/scripts/build-backend.ts b/scripts/build-backend.ts
index a6a3b7c..2dd0a1d 100644
--- a/scripts/build-backend.ts
+++ b/scripts/build-backend.ts
@@ -6,7 +6,7 @@
  */
 import { execSync } from "node:child_process";
 import { existsSync } from "node:fs";
-import { copyFile, mkdir, writeFile, rm } from "node:fs/promises";
+import { mkdir, writeFile, rm } from "node:fs/promises";
 import { arch, platform } from "node:os";
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
@@ -100,13 +100,7 @@ function runTsup() {
   execSync("pnpm tsup", { stdio: "inherit", cwd: ROOT_DIR });
 }
 
-/** 复制 woff2.wasm 到 tsup 输出目录（打包后 __dirname 指向此处） */
-async function copyWoff2Wasm() {
-  const src = join(ROOT_DIR, "vendor/fonteditor-core/woff2/woff2.wasm");
-  const dst = join(ROOT_DIR, "dist_backend/backend/woff2.wasm");
-  await copyFile(src, dst);
-  console.log("Copied woff2.wasm to dist_backend/backend/");
-}
+/** woff2 已使用纯 JS 实现（vendor/fonteditor-core/woff2/index.js），无需复制 wasm */
 
 /** 使用 LLRT compile 生成 .lrt 文件 */
 function runLlrtCompile() {
@@ -126,7 +120,6 @@ function runLlrtCompile() {
 async function main() {
   await ensureLlrt();
   runTsup();
-  await copyWoff2Wasm();
   runLlrtCompile();
 }
 
diff --git a/vendor/fonteditor-core/woff2/woff2-encode.js b/vendor/fonteditor-core/woff2/woff2-encode.js
index 9d59e4f..12d984f 100644
--- a/vendor/fonteditor-core/woff2/woff2-encode.js
+++ b/vendor/fonteditor-core/woff2/woff2-encode.js
@@ -14,14 +14,17 @@ try {
   zlib = require("zlib");
 }
 const brotliCompressSync = zlib.brotliCompressSync;
-const constants = zlib.constants;
+
+/** LLRT 的 zlib 没有 constants，直接使用数值常量（与 Node.js zlib.constants 一致） */
+const BROTLI_PARAM_QUALITY = zlib.constants?.BROTLI_PARAM_QUALITY ?? 3;
+const BROTLI_PARAM_SIZE_HINT = zlib.constants?.BROTLI_PARAM_SIZE_HINT ?? 4;
 
 /**
  * Brotli 压缩参数：quality 8
  * 测试表明 FONT 模式对小数据集（<200KB）无速度优势且增加 0.14% 体积，保持 GENERIC
  */
 const BROTLI_OPTIONS_BASE = {
-  params: { [constants.BROTLI_PARAM_QUALITY]: 8 },
+  params: { [BROTLI_PARAM_QUALITY]: 8 },
 };
 
 /* ======== Known Table Tags 索引表 ======== */
@@ -757,8 +760,8 @@ function encodeTTFToWOFF2(ttfBuffer) {
   /* Brotli 压缩，传入 SIZE_HINT 帮助预分配内部缓冲区 */
   const brotliOptions = totalTableDataSize > 0
     ? { params: {
-        [constants.BROTLI_PARAM_QUALITY]: 8,
-        [constants.BROTLI_PARAM_SIZE_HINT]: totalTableDataSize,
+        [BROTLI_PARAM_QUALITY]: 8,
+        [BROTLI_PARAM_SIZE_HINT]: totalTableDataSize,
       }}
     : BROTLI_OPTIONS_BASE;
   const compressedData = brotliCompressSync(uncompressedData, brotliOptions);