Request Content Evicted from Inspector Cache

Problem Overview

When working with large files (typically 15MB+), you may encounter the "failed to load response data request content was evicted from inspector cache" error in Chrome DevTools. This occurs even when the server returns a successful HTTP 200 status.

Root Cause

Chrome DevTools has a memory limit for storing response data in its cache. Large responses are automatically evicted to preserve browser performance, making them unavailable for inspection in the Network tab.

Solutions

Method 1: Direct Browser Approach

For quick inspection of large responses:

1. Right-click the request in the Network tab
2. Select "Copy" → "Copy as cURL"
3. In the Console tab, paste: var response = await fetch('your-copied-url-here')
4. Execute: var text = await response.text()
5. Type text in console to view the full response

INFO

For JSON responses, use await response.json() instead of await response.text()

Method 2: Command Line with cURL

1. Right-click the request → "Copy" → "Copy as cURL"
2. Paste into your terminal/command prompt
3. Append > response.txt to save to file
4. Execute the command

Example:

curl 'https://your-api-endpoint.com/large-file' \
  -H 'Authorization: Bearer token' \
  > response.txt

Method 3: External Tools

Postman

1. Copy request as cURL
2. In Postman: File → Import → Raw text
3. Paste the cURL command
4. Send request to capture full response

Fiddler

Install and use Fiddler, a web debugging proxy that captures all HTTP(S) traffic without size limitations.

Method 4: Simple Browser Refresh

Sometimes the issue can be resolved by:

1. Closing DevTools completely
2. Reopening DevTools
3. Refreshing the page
4. Triggering the request again

WARNING

This method only works if your response isn't consistently exceeding Chrome's memory limits.

Best Practices for Large Files

Server-Side Optimization

// Instead of sending base64 (which increases size by ~33%)
// Consider sending files as binary data with proper headers

// Express.js example
app.get('/download-large-file', (req, res) => {
  res.setHeader('Content-Type', 'application/octet-stream');
  res.setHeader('Content-Disposition', 'attachment; filename="largefile.bin"');
  fs.createReadStream('/path/to/large/file').pipe(res);
});

Client-Side Handling

// Use streaming for large file downloads
async function downloadLargeFile(url, fileName) {
  const response = await fetch(url);
  const blob = await response.blob();
  const downloadUrl = URL.createObjectURL(blob);
  
  const a = document.createElement('a');
  a.href = downloadUrl;
  a.download = fileName;
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  URL.revokeObjectURL(downloadUrl);
}

Prevention Strategies

1. Increase DevTools Memory Limit (Temporary): Currently no built-in setting, but Chrome may increase limits in future versions

2. Implement Response Chunking: Break large responses into smaller chunks

3. Use File Downloads: For very large files, implement direct download functionality instead of in-memory processing

4. Server-Side Compression: Enable gzip/brotli compression for text-based large responses

Troubleshooting Flowchart

Summary

The "request content was evicted from inspector cache" error indicates Chrome's memory protection mechanism. While inconvenient for debugging, it protects browser stability. The solutions provided offer alternative methods to capture and analyze large responses without relying on DevTools' limited cache.