HTTP Responses and status codes

Question 1

What are HTTP response status codes?

Answer 1

They are issued by a server in response to a client’s request. The first digit of the status code specifies one of five standard classes of responses. Optional messages and body can be sent along with them.

Question 2

Who maintains the official registry of HTTP status codes?

Answer 2

The Internet Assigned Numbers Authority (IANA).

Question 3

How many response classes are there?

Answer 3

5.

Question 4

What are the 1xx HTTP Response classes?

Answer 4

1xx informational response – the request was received, continuing process

Question 5

What are the 2xx HTTP Response classes?

Answer 5

2xx successful – the request was successfully received, understood, and accepted

Question 6

What are the 3xx HTTP Response classes?

Answer 6

3xx redirection – further action needs to be taken in order to complete the request

Question 7

What are the 4xx HTTP Response classes?

Answer 7

4xx client error – the request contains bad syntax or cannot be fulfilled

Question 8

What are the 5xx HTTP Response classes?

Answer 8

5xx server error – the server failed to fulfil an apparently valid request

Question 9

What are the most common 1xx codes?

Answer 9

100 Continue
101 Switching protocols
102 Processing (used for long processes to stop client timing out)
103 Early Hints

Question 10

What are the most common 2xx codes?

Answer 10

200 OK
201 Created
202 Accepted
203 Non authoritative information (used for transforming proxy e.g. a web accelerator) returning a modified version of the origin’s response
204 No content
205 Reset content
206 Partial content
207 Multi status (multiple separate response codes)
208 Already reported

Question 11

What are the most common 3xx codes?

Answer 11

300 Multiple choices
301 Moved permanently (to a new url)
302 Found / moved temporarily
303 See other
304 Not modified
305 Use proxy to access
306 out of use
307 Temporary redirect
308 Permanent redirect

Question 12

What are the most common 4xx codes?

Answer 12

400 Bad request
401 Unauthorised
402 Payment required
403 Forbidden
404 Not found
405 Method not allowed
406 Not acceptable
407 Proxy Authentication required
408 Request timeout
409 Conflict
410 Gone
411 Length required
412 Precondition failed
413 Payload too large
421 Misdirected request
422 Unprocessable content
429 Too many requests
451 Unavailable for legal reasons

Question 13

What are the most common 5xx codes?

Answer 13

500 Internal server error
501 Not implemented
502 Bad gateway
503 Service unavailable
504 Gateway timeout
505 HTTP version not supported
511 Network authentication required