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HTTP 100 Continue

The server received the request headers and the client should send the body. Free reference, no signup.

100 Continue

MeaningThe server received the request headers and the client should send the body.
WhenA client sent Expect: 100-continue and the server is willing to accept the body.
CausesLarge uploads that wait for permission before sending the body.
FixNothing is wrong if the body then succeeds. If the upload stalls, check the proxy in front of the app.
RetryThe client continues the same request. Do not start a second one.
Alert?No. This is a handshake, not a failure.

Runs in your browser. Nothing you enter is stored.

Most 100s are not an incident

This is a handshake, not a failure.

curl -sS -X POST https://api.trigv.com/v1/events \
  -H "Content-Type: application/json" \
  -H "Accept: application/json" \
  -H "Authorization: Bearer $TRIGV_API_KEY" \
  -d '{"channel":"ops","title":"HTTP 100","level":"warning"}'
Get an API key All status codes

How to use it

  1. Read what 100 means before changing a retry loop.
  2. Check the common causes against the response body and the server log.
  3. Follow the retry note. Retrying a 400 with the same body will fail again.
  4. Alert only in the cases the verdict describes.

About this tool

HTTP 100 Continue means The server received the request headers and the client should send the body. Servers send it when A client sent Expect: 100-continue and the server is willing to accept the body.

Common causes: Large uploads that wait for permission before sending the body. The practical fix is: Nothing is wrong if the body then succeeds. If the upload stalls, check the proxy in front of the app.

Retry: The client continues the same request. Do not start a second one.

Alert on it? No. This is a handshake, not a failure.

Trigv is a push for the moment a status starts mattering, not a log of every response. If the code is one you should hear about, the snippet posts a single event with level error or warning. The status page itself does not call your API.

Questions

What is HTTP 100?

The server received the request headers and the client should send the body.

Should the client retry?

The client continues the same request. Do not start a second one.

Should I alert on it?

No. This is a handshake, not a failure.

How is this different from reading the spec?

The page adds a plain retry note and an alert verdict for people running the service, not only for people parsing the response.

101 Switching Protocols The server is switching protocols, usually to WebSocket. 103 Early Hints The server is sending headers, often Link headers, before the final response. Cron Job Alert Script Wrap a command so a failed, slow, or finished cron job sends a Trigv alert.