HTTP Status Code Flashcards: Meanings, Classes & Use Cases
Learn registered HTTP response status codes by number, reason phrase, class, and practical use case, with current IANA and RFC references.
इस डेक के बारे में
Learn the current IANA-registered HTTP response status codes as a practical recall system, not a loose cheat sheet.
What this deck practices
- Code → meaning: all 61 response codes assigned in the IANA registry snapshot used on 25 August 2026, starting with the registered reason phrase and a concise RFC-based explanation.
- Meaning → code: 27 selective reverse cards for common, atomic retrieval targets. These are not mechanical reversals of every entry.
- Class purpose: exactly five cards for 1xx Informational, 2xx Successful, 3xx Redirection, 4xx Client Error, and 5xx Server Error.
- Confusion sets: 401 vs 403; 301/302/307/308; 409 vs 422; 404 vs 410; 202 vs 204; and 502 vs 504.
The order introduces the five classes and common responses first, broadens through the registered set, and finishes with comparison and reference material. Forward and reverse variants are separated so one card does not immediately reveal another.
Special registry status
Temporary 104 Upload Resumption Supported is clearly marked with IANA’s recorded expiry of 13 November 2026. HTTP 402 is taught as registered but reserved by RFC 9110 for future use. Unused 306 and 418, plus obsoleted 510, live in a separate reference section rather than the ordinary recall sequence. Unassigned codes and ranges are excluded because they have no registered reason phrase or stable meaning to recall. Deprecated 305 is labeled accurately.
Explanations follow the IANA HTTP Status Code Registry and its linked RFC references. Reason phrases are labels, not complete normative semantics. Examples and comparisons are original paraphrases and do not prescribe one universal REST API design.
This is an independent, unofficial educational deck by Flashcards Open Source App. It is not affiliated with, endorsed by, or produced by IANA, the IETF, or the RFC Editor. No competitor deck, RFC prose, copyrighted table, or exam question was copied. The CC0 label applies to the original prompts, explanations, organization, metadata, and generated cover to the extent applicable rights exist; it does not claim ownership of facts or standards text.
इस डेक के कार्ड
कार्ड 1
प्रश्न
What is the purpose of the 1xx HTTP status-code class?
उत्तर
Informational. A 1xx response is interim: it communicates connection status or request progress before the final response.
कार्ड 2
प्रश्न
What is the purpose of the 2xx HTTP status-code class?
उत्तर
Successful. A 2xx response means the request was successfully received, understood, and accepted.
कार्ड 3
प्रश्न
What is the purpose of the 3xx HTTP status-code class?
उत्तर
Redirection. A 3xx response means the user agent needs to take further action to fulfill the request, such as following another URI or using a cached representation.
कार्ड 4
प्रश्न
What is the purpose of the 4xx HTTP status-code class?
उत्तर
Client Error. A 4xx response means the client appears to have made an error; it does not prove that every fault lies in client code.
कार्ड 5
प्रश्न
What is the purpose of the 5xx HTTP status-code class?
उत्तर
Server Error. A 5xx response means the server knows it has erred or cannot perform the requested method.
कार्ड 6
प्रश्न
What does HTTP status code 200 mean?
उत्तर
OK. The request succeeded; the meaning of any response content depends on the request method.
कार्ड 7
प्रश्न
What does HTTP status code 404 mean?
उत्तर
Not Found. The origin server has no current representation for the target resource, or it is unwilling to disclose that one exists. The code does not say whether the condition is temporary or permanent.
कार्ड 8
प्रश्न
What does HTTP status code 301 mean?
उत्तर
Moved Permanently. The target resource has a new permanent URI. For historical reasons, a user agent may change POST to GET when following it; use 308 when method preservation matters.
कार्ड 9
प्रश्न
What does HTTP status code 500 mean?
उत्तर
Internal Server Error. The server hit an unexpected condition that prevented it from fulfilling the request.
कार्ड 10
प्रश्न
What does HTTP status code 201 mean?
उत्तर
Created. The request was fulfilled and created one or more resources. The primary resource is identified by
Location, or by the target URI whenLocationis absent.कार्ड 11
प्रश्न
What does HTTP status code 401 mean?
उत्तर
Unauthorized. The request was not applied because it lacks valid authentication credentials for the target resource. The response includes a
WWW-Authenticatechallenge.कार्ड 12
प्रश्न
What does HTTP status code 503 mean?
उत्तर
Service Unavailable. The server is temporarily unable to handle the request, often because of overload or maintenance. It may send
Retry-After.कार्ड 13
प्रश्न
What does HTTP status code 204 mean?
उत्तर
No Content. The server successfully fulfilled the request and has no additional response content to send.
कार्ड 14
प्रश्न
What does HTTP status code 403 mean?
उत्तर
Forbidden. The server understood the request but refuses to fulfill it. Credentials may be insufficient, or the refusal may be unrelated to authentication.
कार्ड 15
प्रश्न
What does HTTP status code 302 mean?
उत्तर
Found. The target resource is temporarily available at another URI, so future requests should still use the original URI. A user agent may change POST to GET when following it.
कार्ड 16
प्रश्न
What does HTTP status code 400 mean?
उत्तर
Bad Request. The server cannot or will not process the request because of a perceived client error, such as malformed syntax, invalid framing, or deceptive routing.
कार्ड 17
प्रश्न
What does HTTP status code 502 mean?
उत्तर
Bad Gateway. A server acting as a gateway or proxy received an invalid response from an inbound server while trying to fulfill the request.
कार्ड 18
प्रश्न
Which HTTP status code has the registered reason phrase “OK”?
उत्तर
200 OK. It indicates that the request succeeded.
कार्ड 19
प्रश्न
What does HTTP status code 202 mean?
उत्तर
Accepted. The request was accepted for processing, but processing is incomplete and might not ultimately happen.
कार्ड 20
प्रश्न
Which HTTP status code has the registered reason phrase “Not Found”?
उत्तर
404 Not Found. It means there is no current representation for the target resource, or the server will not disclose one.
कार्ड 21
प्रश्न
What does HTTP status code 304 mean?
उत्तर
Not Modified. A conditional GET or HEAD would otherwise have returned 200, but the condition was false, so the client can use its stored representation. A 304 response has no content.
कार्ड 22
प्रश्न
Which HTTP status code has the registered reason phrase “Created”?
उत्तर
201 Created. It means the fulfilled request created one or more resources.
कार्ड 23
प्रश्न
Which HTTP status code means the request lacks valid authentication credentials?
उत्तर
401 Unauthorized. The response challenges the client to authenticate for the target resource.
कार्ड 24
प्रश्न
Which HTTP status code has the registered reason phrase “Internal Server Error”?
उत्तर
500 Internal Server Error. It covers an unexpected server condition that prevented fulfillment.
कार्ड 25
प्रश्न
Which HTTP status code means success with no additional response content?
उत्तर
204 No Content. The action succeeded, and there is no response content to send.
कार्ड 26
प्रश्न
Which HTTP status code means the server understood the request but refuses to fulfill it?
उत्तर
403 Forbidden. Repeating the same request with the same credentials should not be automatic.
कार्ड 27
प्रश्न
Which HTTP status code has the registered reason phrase “Moved Permanently”?
उत्तर
301 Moved Permanently. Future references should use the new permanent URI.
कार्ड 28
प्रश्न
Which HTTP status code means the server is temporarily unable to handle the request?
उत्तर
503 Service Unavailable. Temporary overload or maintenance are typical reasons.
कार्ड 29
प्रश्न
Which HTTP status code has the registered reason phrase “Bad Request”?
उत्तर
400 Bad Request. The server perceives a client-side problem that prevents or discourages processing.
कार्ड 30
प्रश्न
Which HTTP status code means a gateway or proxy received an invalid inbound response?
उत्तर
502 Bad Gateway. The upstream response arrived, but it was invalid.
कार्ड 31
प्रश्न
Which HTTP status code has the registered reason phrase “Accepted”?
उत्तर
202 Accepted. Processing has been accepted but is not complete.
कार्ड 32
प्रश्न
Which HTTP status code tells a conditional GET or HEAD to use a stored representation?
उत्तर
304 Not Modified. The request condition evaluated false, so the stored representation remains valid for this response.
कार्ड 33
प्रश्न
What does HTTP status code 100 mean?
उत्तर
Continue. The server received the initial part of the request and has not rejected it. With
Expect: 100-continue, the client should continue sending the request content.कार्ड 34
प्रश्न
What does HTTP status code 206 mean?
उत्तर
Partial Content. The server is successfully fulfilling a range request by transferring one or more parts of the selected representation.
कार्ड 35
प्रश्न
What does HTTP status code 307 mean?
उत्तर
Temporary Redirect. The resource is temporarily at another URI, and an automatic redirect must preserve the request method.
कार्ड 36
प्रश्न
What does HTTP status code 409 mean?
उत्तर
Conflict. The request cannot be completed because it conflicts with the target resource’s current state. The client may be able to resolve the conflict and resubmit.
कार्ड 37
प्रश्न
What does HTTP status code 504 mean?
उत्तर
Gateway Timeout. A gateway or proxy did not receive a timely response from an upstream server needed to complete the request.
कार्ड 38
प्रश्न
What does HTTP status code 101 mean?
उत्तर
Switching Protocols. The server accepts the client’s
Upgraderequest and names the protocol that will be used after this response.कार्ड 39
प्रश्न
Which HTTP status code means a range request succeeded with only part of the representation?
उत्तर
206 Partial Content. The response carries one or more requested ranges.
कार्ड 40
प्रश्न
Which temporary redirect status code requires method preservation?
उत्तर
307 Temporary Redirect. An automatic redirect must not change the request method.
कार्ड 41
प्रश्न
Which HTTP status code means a request conflicts with the target resource’s current state?
उत्तर
409 Conflict. The client may be able to resolve the state conflict and try again.
कार्ड 42
प्रश्न
Which HTTP status code means a gateway timed out waiting for an upstream server?
उत्तर
504 Gateway Timeout. The upstream response did not arrive in time.
कार्ड 43
प्रश्न
What does HTTP status code 102 mean?
उत्तर
Processing. This registered interim response says the server accepted the complete request but has not finished processing it; a final response still follows.
कार्ड 44
प्रश्न
What does HTTP status code 203 mean?
उत्तर
Non-Authoritative Information. The request succeeded, but a transforming proxy modified the enclosed content from the origin server’s 200 response.
कार्ड 45
प्रश्न
What does HTTP status code 308 mean?
उत्तर
Permanent Redirect. The resource has a new permanent URI, and an automatic redirect must preserve the request method.
कार्ड 46
प्रश्न
What does HTTP status code 410 mean?
उत्तर
Gone. Access to the target resource is no longer available at the origin server, and the condition is likely permanent.
कार्ड 47
प्रश्न
What does HTTP status code 501 mean?
उत्तर
Not Implemented. The server does not support functionality required to fulfill the request, such as an unrecognized method it cannot support for any resource.
कार्ड 48
प्रश्न
What does HTTP status code 103 mean?
उत्तर
Early Hints. This interim response carries header fields the server is likely to include in the final response, letting the client make safe performance optimizations while it waits.
कार्ड 49
प्रश्न
What does HTTP status code 205 mean?
उत्तर
Reset Content. The request succeeded, and the server wants the user agent to reset the document view that caused the request. The response has no content.
कार्ड 50
प्रश्न
Which permanent redirect status code requires method preservation?
उत्तर
308 Permanent Redirect. Future requests should use the new URI without changing the method during automatic redirection.
कार्ड 51
प्रश्न
Which HTTP status code says a resource is no longer available and is likely gone permanently?
उत्तर
410 Gone. Use 404 when the server does not know whether the absence is permanent.
102 कार्ड
HTTP Status Code Flashcards: Meanings, Classes & Use Cases
इस डेक से मुफ़्त में पढ़ेंपढ़ाई शुरू करने के लिए Flashcards खुलेगा।
कार्ड 52
प्रश्न
Which HTTP status code means the required server functionality is unsupported?
उत्तर
501 Not Implemented. It applies when the server cannot support the functionality needed to fulfill the request.
कार्ड 53
प्रश्न
What does HTTP status code 207 mean?
उत्तर
Multi-Status. The response reports status for multiple independent operations, as defined for WebDAV.
कार्ड 54
प्रश्न
What does HTTP status code 300 mean?
उत्तर
Multiple Choices. The target has more than one representation, and the response provides alternatives so the user or user agent can choose.
कार्ड 55
प्रश्न
What does HTTP status code 405 mean?
उत्तर
Method Not Allowed. The origin server knows the request method, but the target resource does not support it. The response includes an
Allowfield.कार्ड 56
प्रश्न
What does HTTP status code 505 mean?
उत्तर
HTTP Version Not Supported. The server does not support, or refuses to support, the major HTTP version used in the request.
कार्ड 57
प्रश्न
What does HTTP status code 208 mean?
उत्तर
Already Reported. Inside a WebDAV multistatus response, it avoids repeatedly enumerating descendants of another binding to the same collection.
कार्ड 58
प्रश्न
What does HTTP status code 303 mean?
उत्तर
See Other. The
LocationURI identifies a different resource that can provide an indirect response; the user agent retrieves it with GET or HEAD.कार्ड 59
प्रश्न
What does HTTP status code 406 mean?
उत्तर
Not Acceptable. The target has no current representation acceptable under the request’s proactive negotiation fields, and the server will not send a default.
कार्ड 60
प्रश्न
What does HTTP status code 506 mean?
उत्तर
Variant Also Negotiates. The server has a transparent content-negotiation configuration error: the chosen variant is itself configured to negotiate.
कार्ड 61
प्रश्न
What does HTTP status code 226 mean?
उत्तर
IM Used. The server fulfilled a GET by returning the result of one or more instance manipulations applied to the current representation, identified in the
IMresponse field.कार्ड 62
प्रश्न
What does HTTP status code 305 mean?
उत्तर
Use Proxy — deprecated. It was defined to direct access through a proxy, but RFC 9110 marks the status code deprecated. New implementations should not rely on it.
कार्ड 63
प्रश्न
What does HTTP status code 407 mean?
उत्तर
Proxy Authentication Required. The client must authenticate to a proxy for this request. The proxy sends a
Proxy-Authenticatechallenge.कार्ड 64
प्रश्न
What does HTTP status code 507 mean?
उत्तर
Insufficient Storage. The server cannot store the representation needed to complete the method. WebDAV defines this as a temporary condition.
कार्ड 65
प्रश्न
What does HTTP status code 408 mean?
उत्तर
Request Timeout. The server did not receive a complete request message within the time it was prepared to wait.
कार्ड 66
प्रश्न
What does HTTP status code 508 mean?
उत्तर
Loop Detected. The server terminated a WebDAV operation after finding an infinite loop while processing a
Depth: infinityrequest.कार्ड 67
प्रश्न
What does HTTP status code 412 mean?
उत्तर
Precondition Failed. One or more conditions in the request fields evaluated to false against the current resource state.
कार्ड 68
प्रश्न
What does HTTP status code 511 mean?
उत्तर
Network Authentication Required. The client must authenticate to gain network access. It is intended for an intercepting proxy, such as a captive portal, not an origin server.
कार्ड 69
प्रश्न
What does HTTP status code 413 mean?
उत्तर
Content Too Large. The server refuses to process the request because its content is larger than the server is willing or able to process.
कार्ड 70
प्रश्न
What does HTTP status code 411 mean?
उत्तर
Length Required. The server refuses the request without a defined
Content-Length; the client can retry with a valid value.कार्ड 71
प्रश्न
Which HTTP status code means a request precondition evaluated to false?
उत्तर
412 Precondition Failed. The method is not applied when the stated condition does not match the resource’s current state.
कार्ड 72
प्रश्न
Which HTTP status code asks the client to authenticate for network access rather than to the origin server?
उत्तर
511 Network Authentication Required. It is designed for intercepting network proxies such as captive portals.
कार्ड 73
प्रश्न
What does HTTP status code 414 mean?
उत्तर
URI Too Long. The server refuses the request because the target URI is longer than it is willing to interpret.
कार्ड 74
प्रश्न
Which HTTP status code means the request content is too large to process?
उत्तर
413 Content Too Large. The refusal is about the size of the request content, not the URI or request headers.
कार्ड 75
प्रश्न
What does HTTP status code 415 mean?
उत्तर
Unsupported Media Type. The origin server refuses the request because its content format is unsupported for this method on the target resource.
कार्ड 76
प्रश्न
What does HTTP status code 416 mean?
उत्तर
Range Not Satisfiable. The requested ranges were rejected because none can be satisfied or because the request contains too many small or overlapping ranges.
कार्ड 77
प्रश्न
What does HTTP status code 422 mean?
उत्तर
Unprocessable Content. The server understands the content type and the syntax is correct, but it cannot process the contained instructions.
कार्ड 78
प्रश्न
What does HTTP status code 417 mean?
उत्तर
Expectation Failed. At least one inbound server could not meet the expectation stated in the request’s
Expectfield.कार्ड 79
प्रश्न
Which HTTP status code means the request content format is unsupported for the target method?
उत्तर
415 Unsupported Media Type. The issue can come from
Content-Type,Content-Encoding, or inspecting the data itself.कार्ड 80
प्रश्न
What does HTTP status code 421 mean?
उत्तर
Misdirected Request. The request reached a server that cannot or will not produce an authoritative response for that target URI on the received connection.
कार्ड 81
प्रश्न
What does HTTP status code 423 mean?
उत्तर
Locked. In WebDAV, the source or destination resource for the method is locked.
कार्ड 82
प्रश्न
Which HTTP status code means syntactically correct content cannot be processed?
उत्तर
422 Unprocessable Content. The content type is understood and the syntax is valid, but the contained instructions cannot be processed.
कार्ड 83
प्रश्न
What does HTTP status code 424 mean?
उत्तर
Failed Dependency. The requested action depended on another action, and that other action failed.
कार्ड 84
प्रश्न
What does HTTP status code 425 mean?
उत्तर
Too Early. The server is unwilling to risk processing a request that might be replayed, such as a request sent in TLS early data.
कार्ड 85
प्रश्न
What does HTTP status code 429 mean?
उत्तर
Too Many Requests. The user sent too many requests in a given time. The response may include
Retry-After.कार्ड 86
प्रश्न
What does HTTP status code 426 mean?
उत्तर
Upgrade Required. The server refuses the current protocol but might perform the request after the client upgrades. The response states the required protocol in
Upgrade.कार्ड 87
प्रश्न
What does HTTP status code 428 mean?
उत्तर
Precondition Required. The origin server requires a conditional request, commonly to prevent a lost update when resource state changes between reading and writing.
कार्ड 88
प्रश्न
What does HTTP status code 431 mean?
उत्तर
Request Header Fields Too Large. The server refuses to process the request because all request headers together, or one particular header, are too large.
कार्ड 89
प्रश्न
Which HTTP status code is registered for rate limiting?
उत्तर
429 Too Many Requests. It indicates too many requests in a given amount of time.
कार्ड 90
प्रश्न
What does HTTP status code 451 mean?
उत्तर
Unavailable For Legal Reasons. Access is denied because of a legal demand. The code does not establish whether the resource exists.
कार्ड 91
प्रश्न
How do HTTP 401 and 403 differ?
उत्तर
401 Unauthorized means the request lacks valid authentication credentials and includes an authentication challenge. 403 Forbidden means the server understood the request but refuses it; credentials may be insufficient or irrelevant to the refusal.
कार्ड 92
प्रश्न
How do HTTP 301, 302, 307, and 308 differ?
उत्तर
301 is permanent and may change POST to GET. 302 is temporary and may change POST to GET. 307 is temporary and preserves the method. 308 is permanent and preserves the method.
कार्ड 93
प्रश्न
How do HTTP 409 and 422 differ?
उत्तर
409 Conflict is about a conflict with the target resource’s current state. 422 Unprocessable Content is about understood, syntactically correct request content whose instructions cannot be processed. Neither code dictates one universal REST API policy.
कार्ड 94
प्रश्न
Which HTTP status code means access is denied because of a legal demand?
उत्तर
451 Unavailable For Legal Reasons. The response can explain the legal demand and who it affects.
कार्ड 95
प्रश्न
How do HTTP 404 and 410 differ?
उत्तर
404 Not Found does not say whether the missing representation is temporary or permanent and can also hide a resource’s existence. 410 Gone says the resource is no longer available and the condition is likely permanent.
कार्ड 96
प्रश्न
How do HTTP 202 and 204 differ?
उत्तर
202 Accepted means processing was accepted but is not complete and may never happen. 204 No Content means the request was successfully fulfilled and there is no additional response content.
कार्ड 97
प्रश्न
How do HTTP 502 and 504 differ?
उत्तर
502 Bad Gateway means the gateway or proxy received an invalid upstream response. 504 Gateway Timeout means it did not receive the needed upstream response in time.
कार्ड 98
प्रश्न
What does HTTP status code 104 mean, and what is its registry status?
उत्तर
Upload Resumption Supported — temporary. It is an informational response indicating resumable-upload support. IANA records registration on 13 November 2024, an extension on 15 September 2025, and expiry on 13 November 2026.
कार्ड 99
प्रश्न
What does HTTP status code 402 mean?
उत्तर
Payment Required — reserved for future use. IANA registers the reason phrase, but RFC 9110 does not define a general operational meaning. Treat application-specific payment uses as conventions, not universal HTTP semantics.
कार्ड 100
प्रश्न
What is the current registry status of HTTP 306?
उत्तर
Unused and reserved. RFC 9110 says 306 was defined previously, is no longer used, and remains reserved. It is not an ordinary redirect code.
कार्ड 101
प्रश्न
What is the current registry status of HTTP 418?
उत्तर
Unused and reserved. IANA does not register “I’m a Teapot” as the current reason phrase. RFC 9110 keeps 418 unavailable for other assignments because the joke code was widely deployed.
कार्ड 102
प्रश्न
What is the current registry status of HTTP 510?
उत्तर
Not Extended — obsoleted. The historical code said an extension policy was not met, but IANA marks it obsoleted after the HTTP extension experiments moved to Historic status.
102 कार्ड
HTTP Status Code Flashcards: Meanings, Classes & Use Cases
पढ़ाई शुरू करने के लिए Flashcards खुलेगा।