Example HTTP Response
HTTP/1.1 100 Continue- Client sent Expect: 100-continue header
- Server acknowledging it's ready for the request body
- Large file uploads checking if server is ready
What does this mean?
The server is saying 'Keep going, I'm listening!' Like a friend nodding along as you tell a story.
Technical Definition
The server has received the request headers and the client should proceed to send the request body.
RFC Says
"The 100 (Continue) status code indicates that the initial part of a request has been received and has not yet been rejected by the server. The server intends to send a final response after the request has been fully received and acted upon."
Plain English:
100 means 'I've read your headers and they look OK - go ahead and send me the rest of the request body.' It's used with the Expect: 100-continue header to avoid sending large request bodies if the server will reject them anyway.
Common Misinterpretation
Don't confuse this with request completion. 100 is just the server saying 'continue sending' - you'll still get a final response (like 200 or 400) after the full request is processed.
Ready-to-use code for returning this HTTP status in your application:
// Express.js
app.get('/example', (req, res) => {
res.status(100).json({
error: 'Continue',
message: 'Your error message here'
});
});
// Native HTTP
const http = require('http');
http.createServer((req, res) => {
res.writeHead(100, { 'Content-Type': 'application/json' });
res.end(JSON.stringify({
error: 'Continue',
message: 'Your error message here'
}));
}).listen(3000);