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HTTP-statuscode-referentie
Alle geregistreerde HTTP-statuscodes, doorzoekbaar en filterbaar per klasse — met heldere uitleg over wat elke code werkelijk betekent.
Continue
The server received the request headers; the client should proceed to send the body.
Switching Protocols
The server agrees to switch protocols as requested via the Upgrade header (e.g. to WebSocket).
Early Hints
Preliminary headers (mostly Link preload hints) sent before the final response.
Created
The request succeeded and a new resource was created — typical for POST endpoints.
Accepted
The request was accepted for asynchronous processing; completion is not guaranteed.
Non-Authoritative Information
The response was modified by a transforming proxy from the origin's 200 response.
No Content
The request succeeded but there is no body to return — common for DELETE or PUT.
Reset Content
The request succeeded; the client should reset the document view (e.g. clear a form).
Partial Content
The server is delivering only part of the resource due to a Range header.
Multi-Status
WebDAV: the body contains multiple status codes for multiple sub-operations.
Already Reported
WebDAV: members of a binding were already enumerated in a previous reply.
IM Used
The response is a delta (instance manipulation) applied to the current resource.
Multiple Choices
Several representations exist for the resource; the client should pick one.
Moved Permanently
The resource moved permanently to a new URL. Browsers and crawlers update their references.
Found
Temporary redirect. The client should keep using the original URL for future requests.
See Other
The response is at a different URI and should be fetched with GET — typical after a POST.
Not Modified
The cached version is still valid; the server sends no body. Driven by If-None-Match / If-Modified-Since.
Use Proxy
Deprecated: the resource must be accessed through the proxy given in the Location header.
Temporary Redirect
Like 302, but the client must not change the HTTP method when following the redirect.
Permanent Redirect
Like 301, but the client must not change the HTTP method when following the redirect.
Bad Request
The server cannot process the request due to a client error — malformed syntax, invalid parameters or body.
Unauthorized
Authentication is required or has failed. The response includes a WWW-Authenticate challenge.
Payment Required
Reserved; used in practice by some APIs to signal exhausted quota or required payment.
Not Found
The resource does not exist at this URL. The most common HTTP error on the web.
Method Not Allowed
The HTTP method is not supported for this resource — e.g. POST on a read-only endpoint.
Proxy Authentication Required
Like 401, but authentication is required by an intermediate proxy.
Request Timeout
The server timed out waiting for the client to finish sending the request.
Conflict
The request conflicts with the resource's current state — e.g. concurrent edits or duplicate creation.
Gone
The resource existed but was permanently removed; unlike 404, this is intentional and final.
Length Required
The server requires a Content-Length header and the request did not provide one.
Precondition Failed
A conditional header (If-Match, If-Unmodified-Since…) evaluated to false.
URI Too Long
The request URI is longer than the server accepts — often a symptom of data in the query string.
Unsupported Media Type
The request body's Content-Type is not supported by the endpoint.
I'm a teapot
April Fools' RFC 2324: the server refuses to brew coffee in a teapot. Sometimes used as an easter egg.
Misdirected Request
The request was sent to a server unable to produce a response (e.g. wrong TLS SNI).
Unprocessable Content
The request is well-formed but semantically invalid — the classic validation-error response for APIs.
Failed Dependency
WebDAV: the request failed because a previous dependent request failed.
Too Early
The server refuses to process a request that might be replayed (TLS early data).
Upgrade Required
The client must switch to a different protocol (given in the Upgrade header).
Precondition Required
The server requires the request to be conditional to prevent lost-update conflicts.
Too Many Requests
The client exceeded a rate limit. Check the Retry-After header before retrying.
Request Header Fields Too Large
Headers (individually or collectively) exceed the server's limits — often oversized cookies.
Unavailable For Legal Reasons
Access is denied for legal reasons, such as censorship or court order.
Internal Server Error
A generic unhandled error on the server. The catch-all when nothing more specific applies.
Not Implemented
The server does not recognise or support the request method or functionality.
Bad Gateway
A gateway or reverse proxy received an invalid response from the upstream server.
Service Unavailable
The server is temporarily unable to handle the request — overload, maintenance or a crashed backend.
Gateway Timeout
A gateway or reverse proxy did not receive a timely response from the upstream server.
HTTP Version Not Supported
The HTTP protocol version used in the request is not supported.
Insufficient Storage
WebDAV: the server cannot store the representation needed to complete the request.
Loop Detected
WebDAV: the server detected an infinite loop while processing the request.
Not Extended
Further extensions to the request are required for the server to fulfil it.
Network Authentication Required
The client must authenticate to gain network access — typical of captive portals.
Direct zoeken — geen account, geen limieten.
De vijf statuscodeklassen
1xx — Informatief. Tussentijdse antwoorden terwijl de server doorwerkt: protocolwissels, early hints. Zelden zichtbaar voor eindgebruikers.
2xx — Succes. Het verzoek is ontvangen, begrepen en geaccepteerd. 200 OK is de standaard; API's gebruiken ook 201 voor creatie en 204 voor lege antwoorden.
3xx — Omleiding. De client moet een extra actie uitvoeren, meestal de Location-header volgen. 301/308 zijn permanent, 302/307 tijdelijk, 304 betekent "gebruik je cache".
4xx — Clientfouten. Het verzoek zelf is fout: ongeldige syntaxis (400), ontbrekende authenticatie (401), verboden (403), niet gevonden (404) of rate limiting (429).
5xx — Serverfouten. De server kon een geldig verzoek niet verwerken: onafgehandelde fouten (500), kapotte upstreams (502), overbelasting of onderhoud (503), upstream-time-outs (504). Dit zijn de codes om te monitoren en op te alarmeren.
Direct een melding zodra uw API een 5xx teruggeeft
ContinuumNexus controleert uw endpoints vanuit meerdere regio's en mailt u zodra een statuscode fout gaat.
Veelgestelde vragen
- Wat is het verschil tussen 502, 503 en 504?
- Alle drie komen van een gateway of load balancer vóór uw applicatie. 502: de upstream gaf een ongeldig antwoord. 503: de dienst is niet beschikbaar (overbelasting, onderhoud, gecrasht backend). 504: de upstream antwoordde niet op tijd.
- Wat is het verschil tussen 401 en 403?
- 401 Unauthorized betekent "u bent niet geauthenticeerd" — stuur geldige inloggegevens en probeer opnieuw. 403 Forbidden betekent "u bent geauthenticeerd maar niet gemachtigd" — opnieuw proberen met dezelfde gegevens helpt niet.
- 301 of 302 voor omleidingen?
- Gebruik 301 (of 308) bij een permanente verhuizing — browsers cachen het en zoekmachines dragen rankingsignalen over. Gebruik 302 (of 307) voor tijdelijke omleidingen. Moet de HTTP-methode behouden blijven, kies dan 307/308 boven 302/301.
- Wat betekent 429 Too Many Requests?
- De server past rate limiting toe: u stuurde meer verzoeken dan toegestaan binnen een tijdvenster. Respecteer de Retry-After-header, voeg backoff toe aan uw client of vraag een hoger quotum aan.
- Welke statuscodes moet een uptime-monitor als "down" beschouwen?
- Elke 5xx is een serverfout en zou moeten alarmeren. Of 4xx meetelt hangt van de context af: een 404 op uw health-endpoint is een deploymentfout, terwijl een 401 simpelweg kan betekenen dat de monitor geen inloggegevens heeft. Tools zoals ContinuumNexus laten u de exact verwachte statuscode asserten.