curl Tricks Most Developers Don't Know
telegra.ph
curl can do way more than just GET requests. Here are the tricks I use constantly that most people don't know about. Time Any Request in Detail curl -w "\nDNS: %{time_namelookup}s\nConnect: %{time_connect}s\nTLS: %{time_appconnect}s\nFirst byte: %{time_starttransfer}s\nTotal: %{time_total}s\nSize: %{size_download} bytes\n" -o /dev/null -s https://example.com This is incredibly useful for debugging slow APIs. You can immediately see if the bottleneck is DNS, TLS handshake, or server processing. Bypass DNS /…

Compiled the curl flags I use most for API debugging. Highlights:

  • -w flag for detailed timing (shows DNS, TLS, and server processing time separately)
  • --resolve for testing against specific IPs without changing DNS
  • --retry with exponential backoff for flaky endpoints
  • .curlrc for default settings

The timing breakdown alone has saved me hours of debugging — you immediately see whether the bottleneck is DNS resolution, TLS handshake, or actual server processing time.