1xx Informational

HTTP 100 Continue

The server has received the request headers and the client should proceed to send the request body. This interim response indicates that everything so far is OK and that the client should continue with the request or ignore it if already finished.

Common Causes

  • Client sent an Expect: 100-continue header
  • Large request body being sent in stages
  • Server acknowledging initial headers before full upload

How to Fix

  1. 1No fix needed — this is normal protocol behavior
  2. 2Ensure client correctly handles the 100 response before sending body
  3. 3Check server timeout settings for large uploads

Example

HTTP 100 Continue
POST /upload HTTP/1.1
Expect: 100-continue

→ Server responds 100 Continue
→ Client sends the request body

Related Informational Codes

101

Switching Protocols

102

Processing

103

Early Hints