diff --git a/apps/koa-esm/src/index.js b/apps/koa-esm/src/index.js
index b001bc1..e96a2a0 100644
--- a/apps/koa-esm/src/index.js
+++ b/apps/koa-esm/src/index.js
@@ -77,6 +77,45 @@ router.get('/fetch', async (ctx) => {
   ctx.body = data
 })
 
+// Test case 1: text/plain + JSON body
+router.get('/post-text-plain', async (ctx) => {
+  const res = await axios.post(
+    'https://jsonplaceholder.typicode.com/posts',
+    JSON.stringify({ title: 'foo', body: 'bar', userId: 1 }),
+    { headers: { 'Content-Type': 'text/plain' } }
+  )
+  ctx.body = res.data
+})
+
+// Test case 2: application/x-www-form-urlencoded
+router.get('/post-form', async (ctx) => {
+  const res = await axios.post(
+    'https://jsonplaceholder.typicode.com/posts',
+    'title=foo&body=bar&userId=1',
+    { headers: { 'Content-Type': 'application/x-www-form-urlencoded' } }
+  )
+  ctx.body = res.data
+})
+
+// Test case 3: pure text body
+router.get('/post-pure-text', async (ctx) => {
+  const res = await axios.post(
+    'https://jsonplaceholder.typicode.com/posts',
+    'This is a plain text message',
+    { headers: { 'Content-Type': 'text/plain' } }
+  )
+  ctx.body = res.data
+})
+
+// Test case 4: Buffer body
+router.get('/post-buffer', async (ctx) => {
+  const buffer = Buffer.from(JSON.stringify({ title: 'buffer', body: 'test', userId: 1 }))
+  const res = await axios.post('https://jsonplaceholder.typicode.com/posts', buffer, {
+    headers: { 'Content-Type': 'application/json' }
+  })
+  ctx.body = res.data
+})
+
 // SSE test endpoint - server side
 router.get('/sse-server', async (ctx) => {
   ctx.set('Content-Type', 'text/event-stream')
@@ -90,7 +129,9 @@ router.get('/sse-server', async (ctx) => {
   let count = 0
   const interval = setInterval(() => {
     count++
-    res.write(`event: message\nid: ${count}\ndata: {"count": ${count}, "time": "${new Date().toISOString()}"}\n\n`)
+    res.write(
+      `event: message\nid: ${count}\ndata: {"count": ${count}, "time": "${new Date().toISOString()}"}\n\n`
+    )
     if (count >= 5) {
       clearInterval(interval)
       res.end()
@@ -102,18 +143,18 @@ router.get('/sse-server', async (ctx) => {
 router.get('/sse-fetch', async (ctx) => {
   // Fetch SSE from our own server
   const response = await fetch('http://localhost:3001/sse-server')
-  
+
   // Consume the stream to capture events
   const reader = response.body.getReader()
   const decoder = new TextDecoder()
   let result = ''
-  
+
   while (true) {
     const { done, value } = await reader.read()
     if (done) break
     result += decoder.decode(value, { stream: true })
   }
-  
+
   ctx.body = { message: 'SSE stream consumed', data: result }
 })
 
diff --git a/packages/network-debugger/src/core/request.ts b/packages/network-debugger/src/core/request.ts
index c6174ab..a07b611 100644
--- a/packages/network-debugger/src/core/request.ts
+++ b/packages/network-debugger/src/core/request.ts
@@ -22,10 +22,23 @@ function proxyClientRequestFactory(
 ) {
   const actualFn = actualRequest.write
   actualRequest.write = (data: any) => {
-    try {
-      requestDetail.requestData = JSON.parse(data.toString())
-    } catch (err) {
-      requestDetail.requestData = data
+    // Convert to string at source to avoid IPC serialization issues
+    // Accumulate multiple writes (e.g., multipart/form-data)
+    let chunk: string
+    if (Buffer.isBuffer(data)) {
+      chunk = data.toString('utf-8')
+    } else if (typeof data === 'string') {
+      chunk = data
+    } else if (data != null) {
+      chunk = JSON.stringify(data)
+    } else {
+      chunk = ''
+    }
+
+    if (requestDetail.requestData) {
+      requestDetail.requestData += chunk
+    } else {
+      requestDetail.requestData = chunk
     }
 
     return actualFn.bind(actualRequest)(data)
diff --git a/packages/network-debugger/src/fork/module/network/index.ts b/packages/network-debugger/src/fork/module/network/index.ts
index 73f229a..935f62a 100644
--- a/packages/network-debugger/src/fork/module/network/index.ts
+++ b/packages/network-debugger/src/fork/module/network/index.ts
@@ -182,13 +182,7 @@ export const networkPlugin = createPlugin('network', ({ devtool, core }) => {
           headers: headerPipe.getData(),
           initialPriority: 'High',
           mixedContentType: 'none',
-          ...(request.requestData
-            ? {
-                postData: contentType?.includes('application/json')
-                  ? JSON.stringify(request.requestData)
-                  : request.requestData
-              }
-            : {})
+          ...(request.requestData ? { postData: request.requestData.toString() } : {})
         },
         timestamp: devtool.timestamp,
         wallTime: request.requestStartTime,