The HTTP Status Codes reference is a local lookup table, not a request tool: all 62 rows ship inside the page bundle, each pairing a three-digit number with a color badge, a name and a one-line description, and both the search box and the five class buttons filter that table inside the browser without a single network round trip, so you can open the HTTP Status Codes reference and start typing before anything leaves your machine.
The 62 rows and their five classes
The table groups the 62 rows into five classes with counts of 4, 10, 8, 29 and 11: Informational (blue badges), Success (green), Redirection (yellow), Client Error (orange) and Server Error (red). Each row prints the code, the localized name, the class label and a one-line description, and the names and descriptions are translated for all seven site languages, so the same row reads its own version in each language. What the row describes is the status line, not the payload: when a 2xx response carries a JSON body, the JSON Formatter is where that payload gets inspected.
How the search box matches
Search matches a case-insensitive substring against three fields at once: the code as digits, the name and the description. Typing 40 returns exactly the ten rows that begin with 40, because no other code in the table carries that digit pair; typing gateway returns exactly two rows, 502 Bad Gateway and 504 Gateway Timeout, both matched through the name; and typing 404 narrows the whole table to a single row. The description text counts too, which is why a search can hit a row through words that never appear in its name.
How the class filter combines with search
The five class buttons work as a second condition together with the search box: a row must satisfy both to be shown. Clicking a selected class button toggles it back off, and All resets the filter to the whole table. Combine gateway with the 4xx class and the result is zero rows, because both gateway rows are 5xx; the page then prints its empty state "No matching status codes" with the counter "Showing 0 of 62". The same counter is how you read a filter result at a glance: typing webdav matches eight rows scattered across four classes, and the counter confirms Showing 8 of 62 before you have read a single row.
The rows people look up most
Five rows account for most lookups. 404 Not Found says the resource is missing; 502 Bad Gateway and 504 Gateway Timeout both point at an upstream server, one whose answer was invalid and one that never answered in time; 429 Too Many Requests is the rate limit kicking in; and 401 Unauthorized means authentication is required. 204 No Content is the quiet success, a request accepted with nothing to send back. For redirects the descriptions carry the practical difference: 301 Moved Permanently says the resource moved to a new URL, while 308 Permanent Redirect adds that the client must repeat the request with the same method. And yes, the table keeps 418, the teapot row from the RFC 2324 Easter egg specification, in the orange 4xx section.
From the status line to the response body
A status code is one line of the response; everything after it is out of scope for this table. A 200 body can be JSON, HTML or binary, and a 502 body is often a plain text error page from the upstream, so reading the code tells you which layer failed but never what the payload says. The reference itself never sends a request, so the closest it comes to live traffic is the test URL you build around it: when that URL carries query values with spaces, ampersands or unicode, the URL Encoder percent-encodes them so the request line is well formed before you send it.
What this reference is not
It is not a checker: no request is made, no live headers are fetched, and no server log is parsed. It is a desk reference for the 62 rows, with everything else one click away. When a 401 comes with a token, the JWT Decoder opens the token to see which claim failed; when you compare digests to decide whether a body changed, the Hash Generator computes both; when you need to pull status codes out of an access log, the Regex Tester matches the pattern first. For the Content-Type that triggers a bad media type error, the Mime Types guide lists the right value, and when the error body is HTML you want readable, the Format HTML guide shows how to pretty-print it.