diff --git a/bun.config.ts b/bun.config.ts
new file mode 100644
index 0000000..8885ce3
--- /dev/null
+++ b/bun.config.ts
@@ -0,0 +1,18 @@
+import glob from 'fast-glob';
+import dts from 'bun-plugin-dts';
+
+const services = await glob('src/services/*.ts');
+
+await Bun.build({
+  entrypoints: ['src/index.ts', ...services],
+  outdir: './dist',
+  target: 'node',
+  format: 'esm',
+  splitting: false,
+  sourcemap: 'none',
+  minify: false,
+  external: ['minio'],
+  plugins: [dts()],
+});
+
+console.log('Build completed!');
diff --git a/package.json b/package.json
index c72adca..e4da053 100644
--- a/package.json
+++ b/package.json
@@ -1,11 +1,9 @@
 {
   "name": "@kevisual/oss",
-  "version": "0.0.12",
+  "version": "0.0.13",
   "main": "dist/index.js",
   "scripts": {
-    "build": "tsup",
-    "dev": "tsup --watch",
-    "dev:lib": "tsup --watch"
+    "build": "bun run bun.config.ts"
   },
   "files": [
     "dist"
@@ -15,6 +13,9 @@
   "license": "MIT",
   "type": "module",
   "devDependencies": {
+    "@types/bun": "^1.3.3",
+    "@types/node": "^24.10.1",
+    "bun-plugin-dts": "^0.3.0",
     "dotenv": "^16.5.0",
     "minio": "^8.0.5",
     "tsup": "^8.4.0"
@@ -35,5 +36,10 @@
   },
   "publishConfig": {
     "access": "public"
+  },
+  "dependencies": {
+    "@types/lodash": "^4.17.21",
+    "fast-glob": "^3.3.3",
+    "lodash": "^4.17.21"
   }
 }
\ No newline at end of file
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
new file mode 100644
index 0000000..efc037a
--- /dev/null
+++ b/pnpm-workspace.yaml
@@ -0,0 +1,2 @@
+onlyBuiltDependencies:
+  - esbuild
diff --git a/src/index.ts b/src/index.ts
index aae370c..1a0950e 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -84,18 +84,20 @@ export class OssBase implements OssBaseOperation {
     let size: number = opts?.size;
     const isStream = opts?.isStream;
     if (!isStream) {
-      if (data instanceof Object) {
-        putData = JSON.stringify(data);
-        size = putData.length;
-      } else if (typeof data === 'string') {
+      if (typeof data === 'string') {
         putData = data;
         size = putData.length;
       } else {
-        putData = data;
+        putData = JSON.stringify(data);
+        size = putData.length;
       }
     } else {
       putData = data as any;
-      size = null;
+      // 对于流式上传，如果没有提供 size，会导致多部分上传，ETag 会是 ****-1 格式
+      // 必须提供准确的 size 才能得到标准的 MD5 格式 ETag
+      if (!size) {
+        throw new Error('Stream upload requires size parameter to avoid multipart upload and get standard MD5 ETag');
+      }
     }
     if (opts?.check) {
       const obj = await this.statObject(objectName, true);
diff --git a/tsup.config.ts b/tsup.config.ts
deleted file mode 100644
index 9797437..0000000
--- a/tsup.config.ts
+++ /dev/null
@@ -1,16 +0,0 @@
-import { defineConfig } from 'tsup';
-import glob from 'fast-glob';
-const services = glob.sync('src/services/*.ts');
-
-export default defineConfig({
-  entry: ['src/index.ts', ...services],
-  target: 'node22',
-  splitting: false,
-  sourcemap: false,
-  clean: true,
-  format: 'esm',
-  external: ['minio'],
-  dts: true,
-  outDir: 'dist',
-  tsconfig: 'tsconfig.json',
-});